Just because a group of people who have to massively inconvenience themselves and spend four times longer eating their daily calories than someone who gets their protein from meat can do it doesn’t mean that meat is suddenly a “choice” and not necessary.
That’s like saying because some people can ride their bicycles everywhere that cars and public transit are “purely a choice.” You think everyone can live life like you, and have no conceptualization that most of humanity doesn’t live in your location with access to your grocery options and your lifestyle.
That’s before we even get into things like how vegan men often suffer from ED and eating meat virtually instantly cures them. Good luck putting on any muscle as a vegan unless you have no job and can spend all day shoveling buckets if quinoa and lentils down your throat for six straight hours.