It did in fact make me think and I thank you for that. You won't like the outcome of that thinking, though.

First of all, I'm far far away from being "mobilized". I do agree that you could call what the killer did "terrorism" though, as he seeks to influence behavior by mortal fear (terror). Wheter the end justifies the means (as some would argue for example for "eco-terrorism) I don't know. But I see how some people may feel like all other, more civil, avenues to change their life and the system for the better have been blocked off. But again, I'm far from being "mobilized" as in encouraging such behavior or even picking up a gun myself.

Now why did I laugh at the response? Simple: It's morbid and unexpected, which are two aspects that I often find humorous.

Do I feel bad about laughing? No. The reason and the main difference to the "hate speech" you refer to are twofold: First, this joke is punching up, not punching down, as hate speech usually is. Second, hate speech is usually about what people are (black, asian, transgender, gay). This guy in contrast was loathed for what he did. That's a major difference, since you can't change what you are but what you do is in your hands.

I would love to hear a response from you but the condescension and smugness in your tone of writing makes me think that this won't make you think.