Hey, uh, that's not what this means. This means it rests with Americans. If some group commits a crime roughly in proportion to their prevalence in the population, it means that group identity is irrelevant.

Gender identity: man vs woman is very very important. Men ~50x more dangerous. Yes, fifty times. (95% confidence interval: 20x to 100x.)

Trans identity: dunno. Sample size too small. With this one event, 95% confidence interval ranges from "trans men are as dangerous as cis women" through to "trans men are three times as dangerous as cis men". That is: trans men are human. Okay then!

Racial identity (presumably race-associated culture in actuality): not very important (in comparison).

Cultural context: very very important. Fifty times more likely to be a mass shooter if you live in the U.S. than if you live in Japan. (Mass murder with other weapons has a smaller disparity, but it's still over 10x worse in the U.S..)