Personally when I wear makeup in RL it's because I enjoy it, not because I feel socially coerced, or out of some desire to impress or deceive others. Bright geranium red lipstick is a particular favorite- about as unnatural as it gets, I guess. The natural argument is a funny one- not wearing makeup looks natural, but the desire to express and ornament ourselves is also natural, found in many other species, going back untold years. Natural in appearance or natural in behavior- what matters to me is the ability to choose and not be judged unkindly for it, either way.
Touching on what LostInReverie19 said about it not being limited to women and girls, I 100% agree. I look forward to a time when all genders can play with makeup without negative social repercussions. It will be awesome!