Hopefully never. Speech, even horrific speech, even speech in support of the US's enemies, is NOT treason in the legal or constitutional sense and hopefully never will be.
See, this is a hard one for me, because I 95% agree with you 100%

. I think what you said is 100% true in the past. If you were a US citizen and choose to support Lenin or Saddam, or Milosevic, we'd consider you an idiot and move on. There is something different in todays world, however, where information and disinformation campaigns are a form of warfare. This is even more true when it comes to an elected official or news personality, like Tucker, who with their speech are providing Russians exactly what they need to wage and justify war in the digital age. If they were not, those clips would not be utilized in Russian propaganda they way they have been.
More than ever in history, information, disinformation, and our connectedness through social media and other avenues of communication is weaponized. In this line of thinking, it could very well be argued that the language used and clips provided by Tulsi, by Tucker, by Cawthorne, Trump, and their ilk is no different than providing bullets for an enemies gun.
This is a scary thought when it comes to freedom of speech, I agree, but... it is very hard to argue, that their words are not providing aid and comfort when used by Russian propogandists.