I'm surprised this was removed from unpopular opinion, but I haven't read their rules, and some people do not tolerate nuanced thought.
It is unpopular to express sympathy for the young man, and even for his parents, but I agree with you it is very sad that he felt like he had to do this (for whatever reason he believed). And hearing that anyone was described as a loner, and severely bullied in school is very sad.
I see parallels with school shooters that we have in America. People generally don't empathize or mourn the school shooter. The shooter lashes out in a violent way, but we don't spend a lot of time asking why, or digging into the root causes. They are mostly dismissed as monsters of society.
I don't condone the violence, and don't wish to see it replicated. But I assume that most people are multifaceted, and aren't one dimensionally good or bad.