If you want to be vegan, more power to you. But please talk to your doctor first (and optionally do a bunch of reading from non-specifically-vegan sources about how the food is grown). The nutrition-feasibility, health benefits, and current, real-world environmental impact are frequently and loudly lied about by vegans.
You said that two incredibly different things were very similar because of a single trait they share with many other things. Many people are going to point out the laundry list of significantly more important differences in contrast to the one similarity you see.