I think the primary purpose is to raise awareness -- not to dance on any graves. It might feel like a round about way to do it, but I think it's impactful. It tells people who might be anti-vax "Look, these people who have been part of the misinformation efforts died from this shit, it's real man".
Come on. We are all parents here. You know that if your kid makes a mistake and you let them make it (like forgetting to pack their homework), and then the teacher comes down on them, and you are there pointing at them and saying "that's what you get for not packing your homework" your kid is just going to keep doing the behavior just to spite you. Making things even more political is not impactful. I bet you it changes zero minds and may even make some people so resentful they do the opposite just to spite you. Because when it comes down to it, a lot of us are just overgrown children. There is nothing persuasive about this.
The only thing post like this do is dance on graves: it makes the original poster feel superior and smug because they are right, and the shlub idiot is wrong. It's basically saying: "Look at the idiot...they got what's coming to them...and aren't I great for not being an idiot like that person." It's about the poster, not the message they are trying to convey. And it's another symptom of the smug superiority complex that seems to be rampant in society, particularly among our elites, which then you shouldn't be surprised when you get a counter reaction from people like Trump because people want to give the finger to you right back.