I was raised by parents who were married, and would never support premarital sex, yet I am not against premarital sex at all. you cannot judge someones views and morals based on how their parents were.
as far as the topic, yes I wouldn’t reject someone just because their parents weren’t married at the time of conception. To me, everyone is born innocent, doesn’t matter if their parents were married or not. no one is ‘illegitimate’.