yuck someone else's yum even if I feel weird about the whole thing 🤷‍♀️

I'm quite the same honestly, but like you said - there isn't a need to be a dick about it, already a surplus of them around.

In terms of birth defects, that may be right. But it really depends on the generation of in-breading. A single generation wouldnt do much harm but has the potential to if it continues. Of course, about the trauma and power dynamic bits, that may be a hit or miss as it doesn't really hold.