This isn't misinformation. The MAGA gang were trying to do that. They were trying to score political points from it. They still are.

Of course, they were also correct. But these quoted statements are primarily about intention and motive, not really arguing (or even speculating particularly strongly) that the shooter actually was MAGA.

Incidentally, this does not seem like particularly dangerous misinformation at all. MAGA supporters are probably the safest group in America (it is, after all, not a safe country for anyone).