Earlier quoted context omitted.
I've been on Reddit since 2008 myself and was an avid user of forums etc for years before that. When I started on Reddit there was already an element of things having changed, a move away from niche technology discussion towards lowest common denominator stuff and discussion by meme. In general this was fine as you could just move to smaller subreddits, and the bigger pages had fun cultures that permeated the others…
Reddit always had an element of \dchan in it ever since user subs were created. Coontown (and the preceding slur subreddit), FPH etc. In my view this is just a symptom of the wider populace gaining access to internet forums and the cultural shift mass internet usage brought. As in, there have always been darker corners of the internet, just that the people who frequented them had to have some level of nerdiness/geeki…
Back in 2010 there would be discussions about places like /r/jailbait, about the tradeoffs between free speech and public safety etc. Now there are subreddits openly sharing child pornography with links to the social media accounts of the children and their families, and Reddit auto responds that these things don't violate their usage policies when reported.