I don't think the vast majority of people on Reddit would consider just written profanity on its own to be NSFW. And if your post had an actual rating, there's zero chance it would be higher than PG-13, and some TV networks would probably borderline rate it TV-PG if it wasn't very inappropriate as a whole but was still clearly not a kids' show. (Think something like a broadcast network sitcom airing in syndication on a cable network.)