Why do vegans say humans are herbivores?

I had a nightmare about people becoming cannibals and cooking human flesh on a barbecue. I wrote about it on another website and this person from India said it was because I ate meat and had a “blood-lust”...was basically pushing cannibalism. Then the subject of Veganism came up later and the same person started cussing out people who said they wouldn’t give up meat & to stop telling them what to eat. Then they send me a message about drinking cow urine as a healing thing. Someone else mentioned “Well cow urine comes from a cow, do they think that it is Vegan?”...😂🤣😂