Much of the report contains grand jury information that can’t be disclosed.

First - "like other classified info" isn't what you appear to think that it is (i.e., it's usually a negotiation with the executive branch... not a power that Congress holds on its own). There could be classified information in there (like "sources and methods) and it would be redacted as well.

Second - Mueller can't disclose it to Congress. Congress would have to petition the court. I have a tough time believing that any court would do that given:
1) The prosecutor's conclusions from those materials are available in the report
2) The prosecutor himself can be called to testify
3) Congress has the power to conduct its own investigation
4) It's clear that they intend to make it public

Third - we aren't ASKING for it. The 420-0 vote a week or so ago made clear that they understand that some materials in the report could not legally be released - clearly referring to rule 6(e) materials and classified materials. What most in Congress are trying to say is that they won't put up with claims of executive privilege.

Might be a summary of the grand jury proceedings. If he gets to parts that cannot be read he can say so and say why.

It has happened before, I have read.

A few courts have interpreted one of the exceptions to Rule 6(e) to include congressional committees. Others have not.

However, the DOJ's standing policy is that it does not - so it's unlikely that they will be included in Barr's report or that Mueller will give a different answer when Barr asks (as hinted in his letter).

Congress would have to go to the courts. See above for why I wouldn't expect them to get it.

However - I don't see why we would need it. The report necessarily draws conclusions from that material and THAT will be clear enough... and there's ZERO chance that a court would approve a release to the public.

I believe, prevents him from directly talking about un-indicted persons in the investigation, so if Trump, Trump Jr or Kushner were targets and not indicted, Barr's decision to not to prosecute or recommend prosecution killed that.

If he's under subpoena from the Congress that should override any "policy".

cannot wait for the full report, because republicans will most likely force Democrats to subpoena for that too. Which could take years.

...and find out exactly what happened with the Barr-Rosenstein conclusions? Does he agree with them?

Or did they take the "independent" action of defining the Report on their own?

Also, did he think it was obstruction of justice when Mr Trump attempted to get Don McGahn to fire him?

And just how strongly did he think there was no "collusion" between Trump campaign and the Russians?

How bothered should America be that we still do not know what Trump and Putin discussed in Helsinki?

Why did Mr Trump lie about the Trump Tower in Moscow, which would have accrued him hundreds of millions of dollars, it was reported.

I think the House Intelligence or Senate Intelligence might be a good place to start getting answers?

Primarily, however they can get to the truth. In private or in public, it doesn't matter.

Him being required to read the report would let us know..... Then we could make the necessary arguments to get that information out into the open.

As Schiff said yesterday, he's seen the evidence (sans report) and it supports collusion/conspiracy.