I don't think it is appropriate, either. Seems very immature. It isn't as if our side just won the World Cup or similar. This is serious business. Then again, in a country where someone like Donald Trump can be taken seriously as a presidential candidate, a lack of seriousness is to be expected.
Perhaps I should elaborate just a bit more. Celebrations at the end of a war, like the parties on VJ day, are understandable. The death of this criminal doesn't mark the end of anything, it is just another milestone in a complex, ongoing situation.