Can you elaborate? I assumed that quarantining a sub was about the posts, rather than the comments. This is based on my experience of every subreddit having lots of offensive comments (granted, mostly downvoted.)
To somewhat further your point, take a look at /r/greentext and /r/4chan. While the posts themselves are only somewhat racist, the comments that accompany them are disgustingly edgy and juvenile - they're not being downvoted however. I don't think anything is likely to be done to these subreddits.
Posts and comments are all contents. Offensive posts will not spawn inoffensive comments. In WPD you can probably get more upvotes by being more offensive. From what I've seen there, it's usually the ones trying to call for basic decency being downvoted.