Just look at the "Hot Shots" movies.

Saddam Hussein was the bad guy, years before he was overthrown.
In fact, the movie even dropped bomb right in his lap.

'Death of a President'. There was no outrage nor retaliation, just a big yawn because it's just a movie.
http://www.imdb.com/title/tt0853096/

The first amendment protects such work.

We've had movies where the president is killed, perhaps you're unaware?

...for posting up threats against the President but it's okay to make a movie?

Hopefully the Secret Service and the FBI do.

and killed or captured the president. Natural disasters, terrorists, aliens, white supremacists, North Koreans (in "Olympus has Fallen" most recently). Not to mention the ones where the president is an evil plot-master, or the puppet of evil plot-masters, despicably conspiring against the world somehow. Its a tired genre, and there's a shortage of acceptable villains, really.

...aren't the characters fictional?

Are there movies like this where current serving Presidents are portrayed?

I can't think of a single one where a leader here hasn't been fictionalized.

It's yet another low-brow comedy movie about the evil American intelligence apparatus hiring a number bumbling idiots to perform a dangerous mission.

to produce here

nor should it be