Dudes want to promote their manhood by how many women they can lay with. This is especially so in disenfranchised communities. When a man can't conquer his world with his mind, then he will usually result to base desires i.e. proving his value by conquering as many women as possible.
Some dudes take it step further and not only want to smash everything but want to impregnate it as well. Some dudes actually take pride in having a bunch of baby mamas. Somehow, for them, it proves their masculinity by virtue of being able to impregnate many women.
I don't see a moral issue with being with multiple women as long as there is structure i.e. polygamy. Where the men and women have cleared defined roles and there is structure to protect and raise children born from under that union. What's ironic is so many women are against polygamy as a social construct yet will date men who are already in committed relationships only to produce children with no structure in place. Which generally causes fractured families on both ends.
Also, I wish dudes would stop using pimp terms for their regular a## lives. You don't have a "main chick", you have a girlfriend. Dudes talking about having a stable when not one chick would buy them a tie at a flea market.
By and large, dudes want to use the idea of having multiple women as an indicator of masculinity. But simply having sex with a bunch of women, in and of itself, does not prove said masculinity.
Peace