Veganism is a cult and a conspiracy to mentally incapacitate people who would otherwise spend their youth as activists. These potential activists are lured in to veganism by ideals such as ending (or at least not contributing to) the suffering of animals. They devote themselves to the vegan diet, but it gives so few nutrients that these individuals are perpetually starving themselves, even if they appear to be eating enough. This gives them such a low level of energy and mental acuity that literally the only thing they can think about is defending veganism from the criticisms of outsiders. If only they didn't fall into the almost inescapable pit of veganism, they could've spent their lives protesting and lobbying for something that actually matters to the left-leaning ideologies.
I imagine the person who invented veganism was an ethnic Kekistani, out to collect keks from thousands/millions of bamboozled vegans. It's almost too perfect to have not been intentional. Either that or people are just complete fucking morons. That's probably the better bet.