Men don’t have to wear makeup except maybe for men appearing on TV, in the movies, or on stage. The main reason for wearing makeup in front of cameras or on stage is that camera lights will cause any imperfections to be magnified and most people want to have a neater, cleaner look. In addition, since everyone else is wearing makeup if a man (or a woman) were to appear on camera without makeup, they would definitely stand out.
Other than that, most men simply don’t want to wear makeup. It’s time consuming to apply and they think it’s not needed to attract a woman. I tend to agree. I don’t want a man to look prettier than me!