For people who do eat meat - that they feel like it is part of their masculinity. I've really noticed it, especially in men, they often believe the concept of not consuming meat is something that threatens their way of life and masculinity.
Meat being associated with masculinity is purely a societal construct - likely being associated with the proteins in meat being necessary to develop muscles in previous periods of history. I'd say it is one of those constructs that would probably be beneficial to leave behind but that is much easier said than done - since it is integrated into our history as a species. In this period of time, we do not actually require meat to get the proteins necessary to maintain healthy muscle as we can outsource it from other food that we couldn't always get access to in the past - like nuts, beans, seeds, etc. I think it is a flawed argument to say that we necessarily require meat for our lives, because we do not. We should honestly admit that it is simply our personal choices to eat meat and not hide behind veils of logic which are actually just rejecting change and moving forward as a species.
Lol not even vegan though, just my opinion on the subject.