Nope. The GOP is made up of three factions: classic conservatives, the Religious Right, and MAGA (the latter two factions share many members.)

I'm reading the shooter as a member of the first group. A MAGA would not have done what he did, but a classic conservative could. The classic conservatives tend to be never-trumpers because they understand that TFG is willfully ignorant of the Constitution and the job description of POTUS. In addition, they still believe that character matters. From what I hear, they're upset over P2025 and -- now --the GOP VP pick. (I know about classic conservatives because I occasionally read their blogs for educational purposes, and that's what my parents were.)

For centuries, the Right has taken an insurrectionist interpretation of the 2A. So it makes sense to me that a never-trumper would use the 2A against someone who said he would be a dictator on day one.