I've seen this sentiment around a bit, and while I'm not going to tell people their feelings are wrong (I did not like the guy and while I would have preferred something else happen to him over murder, he did help support the set of circumstances that made his assassination possible), I find it confusing enough that it makes me question if either my brain works differently around this or if I'm misunderstanding what feeling empathy actually refers to, because to me, it doesn't seem "voluntary" like that.
Like, for me, if something unpleasant happens to someone, I can't really help but to start imagining it and going over what it might be like to be in or around that position and getting emotionally worked up, pretty much automatically. It doesn't really even matter if I'm glad the guy is gone at some level or hated them, my brain gets the immediate gut twist of "damn, that seems like a horrible experience" all the same. Like, it could be someone as heinous as literal Hitler, and even then if some documentary gets into the details of his end my first gut reaction is likely to be a sense of discomfort and something like "it would really suck to wake up one day as someone that's done all that and brought themselves to such a position, imagine what would be going through your head in that situation".
I haven't watched the video as I don't handle blood and gore and such well, and I don't mean this as some kind of judgement or assertion of virtue, it's just a bit confusing to me when people say things like "I have no empathy for guys like that" or "you shouldn't feel empathy for fascists because they don't deserve it" and I'm like, okay, but how? Does your brain just let you decide not do that? Mine seems to just do it automatically regardless of if it feels appropriate or not.