Soy protein was found to be very slightly estrogenic meaning it triggers estrogen receptors. You'd have to eat a shit ton of soy to have any real effect. The only concern is that it may cause a few extra cases of breast cancer in a population of millions. Have you ever seen a thin male with tits from soy? Man tits comes from being fat because being fat increases actual estrogen. Yes man tits are real tits not just fat. Being fat causes a lot of breast cancer too. Soy boys are just sedentary men that eat like shit. Ironically the balanced macronutrients in soy would probably help their physique.  Edit: But yeah it's a meme