If you were to say, make a pro-ISIS video, or Tweet, would you expect to remain unmolested by the authorities in the United States? All societies set boundaries on what is acceptable speech.
I would expect making a pro-ISIS video/tweet to leave me without additional molestation from the government, yes. Probably wouldn't stay up on YouTube, but other sites don't seem to have a problem with such things. (stereotypically, that would be LiveLeak)
You can check out the list of exceptions to free speech in the US here [0]. I disagree with a number of them, but an "ISIS is awesome and this is why" video would fall under none of them. (the same goes for a "Hitler was awesome" video, a "Trump is awesome" video, or a "Trump is a fascist and we need to rise up in violent rebellion" video)
That's fair. Of course, I haven't heard many "censor the internet" calls in regards to 3guys1hammer, though that may just be because of the age. (3guys1hammer was the first that came to mind, though the quantity of ISIS and Cartel execution videos is also rather high)