I would distinguish between the expression as a personal preference and one directed at someone else.
As a personal preference, it may be rooted in a number of different things, some of which may have some form of bigotry involved. It may be that someone with such a preference may be cutting themselves off from all kinds of wonderful potential relationships, but if that’s the case, the only person hurt is themselves. And if what they’re looking for is a partner who shares certain sorts of background experience, religious beliefs, cultural mores, or whatever else, then that’s something that’s important to what will make a happy relationship for them.
I feel much more negative about it as a statement intended to torpedo or denigrate someone else’s relationship or potential relationship. I can see where such statements come from in places that are not necessarily bigoted, but the preservation of culture through generations, as valuable as it is in the abstract, just won’t happen if the people in each generation don’t value it.