As a (former) young male on reddit (and I started out on reddit when it had about 4 subs), I am not seeing much over radicalization done to people. Reddit is big enough that there are many radicals on there.

I am definitely seeing opinions that aren't mainstream, and I have seen some subs self-radicalize. Self-radicalization seems mostly a consequence of more egregious things being upvoted more (e.g I don't even dare think what r/badcopnodonut looks like now) and a refusal to discuss things people see as issues. There is no reason on earth that gamegate went right wing, but the mainstream media sent hate their way and so they shifted away from those.