We can't even talk in this community dedicated to vegans without someone coming along and meatsplaining.

In my experience it is not NEARLY as prevalent as when someone learns that you are vegan or finds out about vegan communities and whatnot. People make countless memes about vegans for example, but when was the last time you saw a meme about someone choosing to eat Halal? Because to my knowledge there is no scientific study on the different experiences of these groups it is impossible to talk about this topic in any way that isn't anecdotal but for what it's worth I have been all over the US and the anecdotal experience that I have had is so overwhelming that I refuse to believe someone is arguing in good faith if they are claiming that, for example, someone eating Halal has even a remotely similar experience to that of vegans.

My guess is that this is because people tend to associate other dietary or lifestyle decisions as being just a different way to live. Like oh, that person is Muslim or Jewish and that influences their diet. And they don't take that as a personal judgement anymore than they do when they learn that that person is Muslim or Jewish to begin with. But with veganism it is usually not something that a person is raised into. It is a decision that that person has made after learning more about the animal agriculture industry and it is usually for ethical reasons primarily. Not because a religious book told them to. Therefore they hear that someone is vegan and are instantly defensive in a way that isn't true with halal, kosher, etc.