To generalise: women are cultured into selfcare. If it is socially acceptable to spend money on your nails, hair, and makeup, then you are also allowed to pay for a yoga class. Women are already ‘sold’ on selfcare, and they are looking for an appropriate activity, to show that they are worth it. True, this isn’t always to their advantage, but they are allowed to spend money on making a home in themselves.
Men show their masculinity in personal disregard. This isn’t limited to acts of bravery in the face of danger. They can take pride in how little care they put into grooming. After all, care for personal appearance is for women and homosexuals. So for a man to actually spend money on themselves (rather than their tools) is a threatening prospect. A man paying for self development is leaving standard masculinity. After all, NOT paying for any type of care PROVES you are a man.