That's a slippery slope fallacy, and no, it's not dangerously close to that. If you make a certain kind of joke, I would have a very hard time believing you were offended by that same kind of joke when those two events happened within hours of each others.

As far as I've seen, people's atitudes towards crude jokes do not change in the space of a few hours. Maybe they might change that quickly if something significant were to happen in that space of time, but I doubt it in this case.