Esker, it's an interesting article, but ultimately I think they credit 4chan with far too much.
Much like here, 4chan is a place where all manner of things are shared and discussed. From funny memes, to politics, to pictures of pets, gardening tips, sex chat etc etc.
Sometimes they do hilarious things; like rigging online competitions for where Justin Bieber should do his next concert (North Korea) or it spawns the best selling card game of the decade (Cards Against Humanity)
There's also a side of it which is Grim- it's gory, porny and talks about all those things that naice ladies on MN don't talk or know about like DOXXING, making omelettes with semen (I'm not even kidding), mock bomb threats and sometimes real bomb threats. Or admittance to murders (All true.)
Some incels might be on 4chan. But it is not incel specific. It is a total shitshow of a website and not for the faint hearted. There's some great stuff there but also some really terrible things that you can never scrub from your brain. Definitely not suitable for young people. (Yet some idiot parents let their 13 year olds on it because they dont know what it is.)
Moral of my ranting is: We are the parents. It is up to us to know what our kids are doing. Just because the online world is not physical- it doesn't mean it cannot harm your children. If anything it is MORE harmful as it is able to reach out to them in the safety of their own homes.
We need to be so much smarter about how we educate our children.