I would guess this policy is the result of ADL, other pro-Israel lobbying groups, and Israel itself, pressuring social media groups as part of their hasbara operation. And perhaps Elon Musk is a Zionist himself (he's certainly friends with many VCs who are).

Miguel de Icaza is a random person to censor. I'm sure it's just a crude, automated policy that goes off the content of the tweet and his account having a large follower count.