I agree with max well when it comes to shidduchim parents try to set up a match that will fit with the family (and of course with the potential young couple) so when it comes to ruling out ppl, the ones with dissimilar backgrounds to their own are most likely to get bumped off the list.
The same principle can be applied to schools parents are very concerned with what they expose their children to. So with Baalei Teshuva in general, the difficulty is that many are holding in different places in yiddishkeit (still becoming frum all the way to fully integrated). So it only stands to reason that parents should express concern about who attends their childs school.