Why do women feel single childless men are obligated to date single-moms???

Me and my 2 roommates were chatting and the subject of SMs came up. I stated to the 1 female roommate that I don't date SMs. She went into a tirade trying to bully me into changing my mind. I calmly explained all my logical reasoning. She got angry and stormed off refusing to talk to me for the rest of the night. Male roommate was on my side but stayed silent on the matter.

I built a career. Refrained from having kids meanwhile until I'm good & ready. So why should I squander all that to use my resources to raise some other man's child? I can pour those resources into my own future biological children and legacy left to them. Why do women think men should just volountarily take losses like this for no particular reason?