Why is my family like this?

I come from a Hispanic family. I am engaged to my fiancé who is black/white. When we had our daughter I decided to give her his last name as that’s how it’s suppose to go according to my fiancé and I. I didn’t mind, after all, we both made her. I knew this was going to be a problem for my family but I didn’t mention anything until they asked who’s last name did she take? I said my fiancé’s. And the they said “and yours too right?” And I said no, just his last name. And everything just escalated. How dare I give my daughter just my fiancé’s last name and not hyphen my last name as well. I said, my last name was going to be lost anyway after I get married. It’s not that i don’t care about my last name, i just think her name should be her fathers last name. Is that so wrong? They said I wouldn’t be able to take her to doctor appointments nor any place because she didn’t have my last name. And now my daughter is 10 months old and damn sure, I take her to the doctors by my damn self sometimes. Because last names don’t mean shit here in the USA. It’s all about birth certificates. LOO My family has never said a word about it after this. But recently I was talking to my grandmother and she said if I ever left my fiancé (not that I’m doing that) I was basically going to be fucked because she doenst carry my last name. I wanted to laugh so bad. My poor family, they have no knowledge.