I agree with your use of “chilling” but more in the traditional sense when it comes to expression: that any censorship/bans/etc will likely have a chilling effect on this type of speech. In this case I think “this type of speech” comes down to people expressing their violent fantasies or plans, and I don’t think it’s bad if we have less of that particular kind of speech. As the classic argument goes, however, you can’t have it both ways with both total freedom of speech and some kind of moderating censorship.

All that said, if we can make our way past the obvious consequences of limiting speech we might get to a more interesting place. In particular I’m more interested in how social media moderation might change our opinions and laws about speech itself. Does everyone’s speech deserve to be treated the same way by the algorithms that decide what gets traction and what doesn’t? Should the algorithms or platforms themselves be restricted in their “speech” in some way? How do we square our desire to allow corporations to develop algorithms to increase commerce when those same algorithms also necessarily foment rage and violence?

I don’t think it’s worth arguing whether free speech is worth protecting (it is, despite the evils you also have to protect) but I do think it’s worth considering how we think about what constitutes speech when commerce, social media platforms, and algorithms come into play.