4chan being gone for good would've been a bad thing regardless of your views. All those people who used to come there and just talk wouldn't just cease to exist nor stop feeling the way they feel. At the very least, it's the devil you know.
Yep, there is a reason the site was operational as long as it was.
Obviously those people will continue to think and exist the way they are. But we can't assume things will slowly start getting better if we continually allow increasingly racist "discourse" and misinformation in our society.