And in some cases, probability. If my daughter told me she was about to marry a muslim and I didn't know anything else about him, I'd be less comfortable than if she said she was about to marry a european, north american, south american, asian or a guy from Oceania. Not because I think muslims are bad, but because I think the probability of a man and his family having hardcore sexist attitudes that could harm my daughter is higher in muslim culture than in european culture. I would trust my daughter to not be an idiot and find a muslim without this background, as there are many... so I wouldn't say I'd be "uncomfortable". But still, I would be a little bit more preocupied.

Also I'd expect to get to know the guy sooner than later so I could form my opinion about him from empirical observation so this is a pretty useless fact... but that's honestly what I would expect.

(I'm also aware that there are enough european men that are assholes and can destroy her partner's life.)

(I'm talking specifically about a daughter here because sadly they are much more vulnerable in this context.)