Youtube's problem as I see it is differentiation. Howard Stern was "edgy" for his time, similar to how some Youtube producers are "edgy". Yet he has no problem attracting advertisers as far as I know (Googling suggests his radio rates in particular were quite high). But it seems like it was/is much easier in traditional advertising to say "I [do / do not] want to advertise with Howard Stern" then it is to say "I [do / do not] want to advertise with PewDiePie". That's really the crux of the problem as I see it, it flat out sounds like Youtube can't do targeted marketing very well (a ding made more painful considering this is the success story of Google Search). Heck, "I do not want to advertise for ISIS recruitment videos" seemed to be a request Youtube couldn't fulfill for a while.
I don't think "edgy" in itself is a problem to many advertisers per se (except for certain step-over-the-line moments) and I agree with you that Youtube is tackling things in a way too crude manner.
Internet culture is taking over the mainstream, demonetisation of edgier content might have a shortterm effect of restricting content, but ultimately, it's unlikely to stop the cultural shift - people want edgier humor, and if it's popular enough it will eventually appear on Twitch, Vimeo or elsewhere.
Brands are happy to be associated with edgy humor if Jimmy Kimmel is producing it: check out the examples on https://www.youtube.com/watch?v=pj8n78AuN3w. They'll soon be comfortable if a YouTube equivalent is doing the same.