I just randomly googled one of the cases -> https://en.wikipedia.org/wiki/2016_Munich_shooting
and perpetrator "was the son of Shiite Muslims from Iran who came to Germany as asylum seekers in the 1990s."
Immediately closed the article
You shouldn't have done that because a few sentences later the wiki describes how he was motivated by other mass shootings, which is precisely what the article is talking about. Was he a white attacker, well yes, but based on the wiki I wouldn't say he was a supremacist.