Whenever there's a TV Tropes link in an answer, I always see messages like 'warnings! TV Tropes link' etc. I've visited TV Tropes, and I don't think there's any graphic explicit content (from what I've seen that is) in that site.
Sometimes even in comments, such warnings are posted, although I think this one was meant to be humorous.
No, not at all. It is just a joke*/meme that people get lost in a rabbit hole of links when going to TV Tropes and get distracted. Similar to how people sometimes describe YouTube's similar videos and people clicking through them all.