The thing with Incel types, especially if you were paying attention to them years ago back when r/Incel was still a thing and they mostly weren't noticed unless you were reading shit about the "Men's Rights" movement (ie - basically the alt-right's misogyny wing), is that yeah, they are mostly kinda sadsack types. Especially at the start. They are guys who, while they probably have some sexist ideas already to one degree to another, are mostly just lonely or feel inadequate because they can't live up to how they perceive their life should be. And so like a ton of people out there, they find an online community that speaks to those needs and takes them in.
The problem is that said groups in this case turn real nasty and most importantly here, serve as a vector for radicalization. They take these lonely bastards in and they help slowly shape their ideology and it can go anywhere from just regular old horrible sexism to terrorist violence.
And of course if Incel isn't your preferred flavour, there's several other options for being indoctrinated into some real nasty misogyny. All of them have or had Reddits too!
PS - the guy in Toronto seems to have very likely been targeting women at this point