Trump sought and actively tried to subvert constitutional government and overturn the results of the presidential election. And what he could not do through the arcane rules and procedures of the Electoral College, he tried to do through the threat of brute force, carried out by an actual mob.
The one possible out is that he hasn’t been completely convicted of the crimes involved yet. I really hope he is soon. It worries me that he might get some court to say “no, he’s not been charged, put him back on the ballot”, and then he is, and then they go “no double jeopardy on taking him off the ballot, we went over this”