I think we shouldn't celebrate the death of another person - regardless of how deserving they may be.
I don't know much about the guy to say if it was warranted. It does seem like a bad idea to kill a government official in such a blatant way in their own country. This seems like one of those times where you'd have some more stealth and deny any involvement (even though everyone knows it was you).
I think there are two major concerns:
1) It appears he didn't inform congress before the attack. I believe he is legally required to do so and that this is at least the second time he has defied that law.
2) He dealt with it in the most Trumpy of ways.
Like, obviously, I'm one of those over the top patriotic types who thinks it awesome that people like your brother signed up
I say this with lots of love: Fuck your patriotism. This type of patriotism is one of the worst thing about American culture. The military isn't some fucking sports team that you get to cheer on and pretend you are a part of.
That was a bit more aggressive than I started with. I just see it all the time. People will wave their stupid little flag, or put giant ones in the bed of their pickup truck, say how much they respect the military and think nothing about the lives destroyed on both sides.