An awful lot of being alive involves reading between the lines. People don't always say exactly what they mean, and events don't always happen like we expect them to. Also, there are a lot of examples out there of things that could be pretty crass, depending on how you look at it. Often the subtext (or, you know, the fronttext) gives us a crucial extra layer of meaning that makes it hilariously rude.
If there's one thing that is guaranteed a laugh from many, it's some good-old fashioned innuendo, or failing that, an example of barely concealed mischief. In many instances, hinting at the NSFW is more fun than spelling it out for everyone to understand. Not that these hints are subtle, of course, but that just adds to the amusement. It's amazing what can stare us right in the face without saying it out loud, or pretending that it isn't.
