So do you think that journalists should not fact check politicians either?

Well, that's certainly Trump's characterization of the situation. Fox News has also been fact-checking him lately and he's similarly outraged. Bottom line, the Founders' remedy to false speech by government officials is the freedom to discuss those lies in an open forum.

He's the president of the United States operating on a private platform owned by a private company! No one should be above reproach on such a platform and that includes the president.

If he doesn't like it, he can direct Lockheed Martin and tell them to spend a couple billion dollars on making Litter. At least then it'll go to something slightly more productive than whatever contracts they're currently siphoning money off of.