Reddit is also /r/haskell, /r/emacs, /r/AskScience, /r/AskHistorians, /r/puremathematics, /r/compsci, /r/art, and many, many others. Notwithstanding that /r/jailbait got banned years ago, sounds like you're being pretty selective here.
If you want to talk about "that excrement", let's talk about the sort of selection bias and language you're using right here.
I came here to say something similar - my exact choice of subreddits varies (ever so slightly) from this list, but there are a lot of small, focused communities that are full of knowledgeable, kind people posting useful information that I would otherwise have no easy mechanism to find. Hacker News is great - and there exist other sites to find interesting news, reading, and products - but only the various specialized subreddits thus far cater to my more esoteric interests. Esoteric interests like academic subjects, not like racism or dumb jokes. I think the key to getting a lot out of reddit is to make an account right away, and tailor a list of actually-interesting subreddits. The front page is a cesspool not just in terms of vitriolic, hateful posts - it's also full of gifs of cats, silly jokes, etc. - and if you use reddit without filtering out such subreddits you'll end up wasting a lot of time on vapid content. All the dumb racist or sexist "humor" is vapid content too - but I'm willing to put up with both sources of worthless links, since I can easily log in and participate in interesting discussions/link-sharing with people who have similar interests. And I have not yet seen a community that enables this as well as reddit does, so I'll be sticking with it for the time being.
18,000 subscribed user accounts out of about 36,000,000. That's .05%, or 1 in 2,000. Except that it's localized in one subreddit that doesn't make the frontpage and is universally reviled on the rest of Reddit.
By all means, leave. People that will leave a public forum because "someone over there is someone I really, really don't like and that every else around me also thinks is vile, but who I am not forced to talk to at any point in time" are generally not valuable users in a forum that is dedicated to open discussion.
I'm not going to go to a pub full of rapists and pedophiles just because the local Linux User Group sets up shop at the corner table.
You might think that's a bad analogy, but that's the reputation Reddit has garnered and I don't think it's insane to not want to be associated with it.
If you want to talk about "that excrement", let's talk about the sort of selection bias and language you're using right here.