For what it's worth, my reaction to the word "bloodline" used in this way is exactly what it would have been to the word "dynasty".

"Bloodline", as in, the line of inheritance for an extremely wealthy and powerful family, like Medieval monarchs.

Perhaps we should be a tad more careful about our language use, but I see far too much outright bigotry to be worried about something obviously not used as a dogwhistle.