Well for one: They have had a monopoly over twitter censorship and feel threatened by this disruption.
No conservative has ever been banned for tweeting about supply-side economics or praising Jesus. It’s the, uh, other “beliefs” that get them banned.
It seems fairly clear that Musk is buying Twitter so he can re-platform conservatives. Why else bother owning it? Influential people on the left will say anything, true or untrue to tank Musk's reputation. Don't get down in the weeds of the talking points, look at who controls political conversation in the US and who stands to benefit if that monopoly is broken. I am on the left, but am increasingly disturbed by the total shut-out of conservatives from social media.