Are vegan men seen as less masculine?

In an article from Medical Daily, a study shows that men who live a vegan lifestyle are seen as less masculine than men who eat meat.

http://www.medicaldaily.com/men-following-vegan-diet-subject-gender-stereotypes-non-meat-eater-seen-less-363164

The study showed that men were not seen as less masculine for not eating meat, it was the reasons why they chose to go vegan that makes them less masculine. Typically, people go vegan for health, environmental, and ethical reasons. They strongly believe in ending animal cruelty and being aware of how the consumption of meat and animal products affects our planet. The study showed that vegan men are still considered masculine only when they go vegan for health reasons.

Why is caring about animals and being environmentally conscious seen as feminine? I think it's a testament to how limiting masculinity is. Even showing concern for important issues somehow makes someone less of a man. This is also important when considering what men are allowed to care about. It's okay for men to be passionate about social/political causes such as gun control or the legalization of marijuana, but other issues are supposed to be seen as issues for women to handle. I found the results of this study completely ridiculous and a perfect example of how pointless it is to place a gender on a movement.