I’m a BT married to an FFB, and there is halachic basis to not want to marry a BT having to do with your mother and going to a mikveh, and this effecting your middos. However, the Chazon Ish approved of his grandson (or great-grandson?) marrying a BT.
In any case, if you don’t like that someone discriminates that way, don’t marry them! Marry someone who agrees with your perspectives on life. You only need one.
I knew a former baptist preacher who converted to Judaism … his father made peace with his conversation to Judaism but said, whatever you do, don’t marry a black girl because he couldn’t accept that. You can guess who he ended up marrying… that ended up being the girl who was right for him.