I think you're being naive if you think Antifa are truly against all of those things, some of them are - some of them just want to smash things up and have a good old riot. As for decision making - if the US authorities have labelled them as a terrorist organisation - as far as I'm concerned, the decision has been made already.
By narrative, I mean a hard left worldview.
Of course, it's their own company - and yes, they can apply their own narrative as much as they want on their own platform, I'm not talking about anybody being forced into doing anything, I just think that a platform such as Facebook, Youtube, Twitter etc - should attempt to be as neutral as possible, and it is in fact a mistake for them to impose Ts & Cs which favour any specific narrative or worldview, because then it's no longer a neutral platform, and then the Ts & Cs won't be applied fairly to everyone, if you start to ban one group of people - you have to go after all of them, it can't be done properly at Facebook scale.
Simply saying; "They're against lies, bullying, racism, hate speech, white supremacy, so we should just let them swing the hammer at anybody who's part of those groups" is problematic, because as soon as someone from Antifa or Blacklivesmatter starts engaging in hate speech or bullying, or even arguably racism (BLM) - they get let off scot free, because the people swinging the ban hammer aren't applying the rules in a uniform manner, their skewed towards their own prejudice.
Intelligent and well educated people are one thing, but then they come from a society which is so totally backward and broken (American society) I'd question a lot of the policies and practises which these companies may implement in their platforms.
Like Google Safesearch - with it turned on, you can find videos of people being killed, islamic state beheading people, murdering, killing, hatred - yet not a single bare breast or backside,
All developed by super clever people, with totally backward and broken views, it's nonsense - yet it's the same for everyone if you turn it on.
I don't think anybody should be forced to do anything, instead people using these global social media platforms, should learn to deal with things they find offensive without relying on some sort of higher authority to sanitise everything for them - look the other way, turn it off, unsubscribe, change the channel, don't click on it, or just deal with it.
It reminds me of that episode of Black Mirror, (Arkangel) where a child gets fitted with an implant, which can filter out dangerous, disturbing or upsetting images from their vision or sound in real life - which at first seems great, but ultimately ends up crippling her and becomes a massive problem, because she's no longer able to make her own mind up about anything - it's all being done by a third party.