This is a cheap bait - of course when there's a small number of leniently moderated popular platforms, there will eventually be a high-profile criminal that would use one of them, because a) that what "popular" means and b) anti-social types would gravitate to more leniently moderated platforms. And of course on the same platforms there would be online edglelords that would make sure to cheer whatever causes the most offense, because that's what they are there for. If you close 4chan, there would be another platform that would become focus of the same people - because the people focus on the platform, not the platform causes the people to become bad. The press that tried to frame it the way which reverses the cause and the effect is doing you a disservice, and you may want to consider using a better source of information. If, of course, you are interested in understanding the causes and the effects of things, not just feeling good by having your preconceptions confirmed.

How many of these used Facebook, Twitter or Reddit? They are not mentioned in mainstream media because they are popular, but I assure you there are a lot of deranged people that never even posted on 4chan and just stuck to the “good” ones.

Do it for 2ch now.