Why do so many people put down masturbation when it has health benefits?

Masturbation can relieve menstrual cramps, relieve stress and ual tension, help you sleep better, and helps your immune system function better. When people have s, their b cells produce more of an antibody called IgA. So less colds. I'm a biology major and plan on being an immunology/allergy doctor or a Ph.D. in immunology.