...that the company gets to make the rules.
These folks that protested on company time had to know, or should have known, the risks.
If they knew the risk & took it anyway, more power to them for putting their principles above their livelihood.
If they didn't assess the risk properly, that's just foolhardy.

don’t apply to private businesses.

The company makes the rules. One is free to leave if one doesn't like the rules.
Break the rules, the company if free to say so long.

Not sure how some of these people got as far as they did without learning some basic lessons.

I have never worked anywhere where I could run around, disrupt work, argue with co-workers, and dump my politics all over everyone around me and expect to retain my job. Like, what is this line? "The corporation is attempting to quash dissent, silence its workers and reassert its power over them."

Yeah. You don't get disruptive performative political activities at work. That is not how that works.

I was watching/listening to some interviews with these people last week, and they seem genuinely baffled that company officers didn't watch the tantrum and come down with, "How can we give you what you want?"

Remove the Israel/Gaza stuff for the moment. It's just interesting to watch. These are ostensibly adults. How privileged must their lives be that anything that follows their actions is a surprise for them? I was watching a Columbia student yesterday who just could not believe people were arrested for breaking the law. Have you ever heard such a thing? Arrests for law-breaking? Outrageous!

All I can think is that they're used to other areas of their lives (probably indulgent parents and college) where adults and higher ups acquiesced to these kinds of tantrums on the regular.

I guess learning this lesson sooner rather than later will probably serve them better.

work conditions with ability to make political statements and protest. Hopefully they learn the difference so at their next job they will know better.

They've seen union strikes and figured, "I can do the same thing about any issue I want."

I can't decide if I feel bad for them or not, because the adults in their lives clearly failed them in a profound way. Tech is a much smaller community than people think. Their names are out there. No one is going to want to hire them.

As ProfessorGAC said, the people who knew they'd probably lose their jobs and still did it. Ok, respect. Seriously. You sacrificed for your beliefs. You knew the consequences and felt that strongly.

But a lot of these people seem to have not seen it coming. They thought the performative was sufficient for concessions. And you just want to say, "Oh, booboo. No. None of this works that way. "

It’s truly a shame their boss of friendly coworkers didn’t take them aside and explain to them that it wasn’t a good idea and why. I think it would have stopped some. Although, maybe some did and rejected the advice. Either way, tough lesson.

The problem with a lot of activists who go this far - particularly in tech - is they'll paint a target on the backs of the people who oppose or disagree with them. The kind of people they needed to hear from were also the kind of people wise enough to keep their heads down.

You nicely elaborated on my sentiment.
It doesn't work that way, indeed.

It’s why they have been self employed for years and sometimes struggle to pay basic bills.

Signing agreements not to strike or unionize, being squelched, being told to be positive no matter what, you don't have free speech at work. I'm Gen X. I found younger workers around me much freer about complaining about the PTB. the local pols. The sucky work conditions. Saying their looking for new jobs. I never did that. I just looked privately.

Its interesting. Btw, the attitude was lump it or leave

employers in the US can generally fire anyone they want provided it isn’t prohibited by law (race, gender, religion, country of origin).

Google, or just about any company that operates for profit, is not in business to provide a platform for employees’ personal or political beliefs, opinions, or views. Are you of the opinion that Google should allow employees to use company time and resources to protest management decisions and policies?

Unionized workers are not allowed to take over the boss's office. Employees can discuss unfair labor practices with each other while they are on break. Employees cannot dictate who their employer does business with. Engaging in these activities allowed an employer to terminate an employee.

From the NLRB

Working time is for work, so your employer may maintain and enforce non-discriminatory rules limiting solicitation and distribution, except that your employer cannot prohibit you from talking about or soliciting for a union during non-work time, such as before or after work or during break times; or from distributing union literature during non-work time, in non-work areas, such as parking lots or break rooms. Also, restrictions on your efforts to communicate with co-workers cannot be discriminatory. For example, your employer cannot prohibit you from talking about the union during working time if it permits you to talk about other non-work-related matters during working time.

Strikes for a lawful object.Employees who strike for a lawful object fall into two classes “unfair labor practice strikers” and “economic strikers.” Both classes continue as employees, but unfair labor practice strikers have greater rights of reinstatement to their jobs.

Unfair labor practice strikers defined.Employees who strike to protest an unfair labor practice committed by their employer are called unfair labor practice strikers. Such strikers can be neither discharged nor permanently replaced. When the strike ends, unfair labor practice strikers, absent serious misconduct on their part, are entitled to have their jobs back even if employees hired to do their work have to be discharged.

Furthermore, Section 8(b)(4) of the Act prohibits strikes for certain objects even though the objects are not necessarily unlawful if achieved by other means. An example of this would be a strike to compel Employer A to cease doing business with Employer B. It is not unlawful for Employer A voluntarily to stop doing business with Employer B, nor is it unlawful for a union merely to request that it do so. It is, however, unlawful for the union to strike with an object of forcing the employer to do so.

Examples of serious misconduct that could cause the employees involved to lose their right to reinstatement are:

Strikers physically blocking persons from entering or leaving a struck plant.
Strikers threatening violence against nonstriking employees.
Strikers attacking management representatives.
https://www.nlrb.gov/about-nlrb/rights-we-protect/the-law/employees/your-rights-during-union-organizing
https://www.nlrb.gov/strikes

The AP has a more detailed article:
I believe Google had the right to terminate them.
I don't believe the bit about "non-participating bystanders". If you are at work, how can you be a bystander?

Google fires more workers who protested its deal with Israel

Google said it fired the additional workers after its investigation gathered details from coworkers who were “physically disrupted” and it identified employees who used masks and didn’t carry their staff badges to hide their identities. It didn’t specify how many were fired.

The company disputed the group’s claims, saying that it carefully confirmed that “every single one of those whose employment was terminated was personally and definitively involved in disruptive activity inside our buildings.”
https://apnews.com/article/google-israel-protest-workers-gaza-palestinians-96d2871f1340cb84c953118b7ef88b3f