This smacks of whataboutism to me. No doubt Facebook hosted large amounts of this activity, but it does not negate the fact that Parler did so as well. Amazon's court filing detailed hundreds of incidents that they had given Parler months to fix.
Husband: Two glasses of white wine in one night honey? You need to cut back for your health's sake
Wife: But dear, you drink a handle of vodka every night and have refused any attempts at intervention.
Husband: A-ha, classic whataboutism
edit: I'd love to respond to the people below me, but HN has decided that one post an hour is too much (despite having a 10 year old account and 4000+ karma)
I don't think anyone is suggesting that Facebook is free of guilt, but there is evidence that Facebook does at least try to keep their site clean, and for the most part they do. Its certainly possible that Facebook had (in absolute terms) more violence and planning than Parler, but as a percentage of the overall content, it's much smaller.
This doesn't excuse Facebook, they can do better, but it isn't hypocritical to say "the group with 10% violent content that tacitly encourages it isn't okay, while the group with .1% violent content that actively innovates in trying to keep things clean is okay".
Of course, that's only true if FB is actively innovating, and, well, that's questionable (Yann Lecun has made some concerning statements about Facebook's role, or lack thereof, in radicalization).