After taking an introductory class in Sociology, I learned that polls are usually misleading. Yes, a lot of studies show that many vegans are not as healthy as they should be. What the studies do not tell you is that most of the unhealthy vegans are not supplementing their diets appropriately. When one cuts out animal-derived proteins completely, one MUST find those proteins elsewhere, or suffer the consequences. Many of the natural sources of omega-3s are cold-water fish. Omega-3 fatty acids are one of the most important things to have in one's diet, and the easiest supplementation for this fatty acid can be found in flax as well as walnuts. I could go on forever about health food, but I have a point to make.
Many of the people who abuse the right to bear arms are also irresponsible. So many violent crimes are committed in the heat of passion, or in the name of revenge. Basically, when one is in the throes of any extreme emotion, one should not devise any permanent solutions to fleeting and temporary problems. You get bullied in school, you graduate in a mere fraction of a lifetime. Your spouse cheats on you, leave and find a hobby. I could go on forever about this, too.
My point is, that most everything in life should be approached in a mature, productive manner. Irresponsible people are the cause of, well, basically all of the laws in existence. If you make the decision to become vegan, research it. Don't just say, "Ahyuck, I'm gonna be a vegan!" The same goes for purchasing something as dangerous as a gun. Learn how to use it properly, so you don't accidently shoot yourself while cleaning it. One would hope that you would ask yourself, "Am I emotionally stable enough to have a gun?" and answer truthfully, but it doesn't look like the world is going in that direction.