Agreed. I'm not a vegan (I eat meat from certifiably "happy" animals) but it's a perfectly understandable position. The only rational conclusion is that people who find veganism confusing are simply looking for a reason to dismiss it.
"No, no, I don't mind being called the smartest man in the world. I just wish it wasn't this one." -- Adrian Veidt/Ozymandias, WATCHMEN