it is extremely load bearing though. at its heart it is a family dynamics problem of fucking up your kids like you were fucked, and no worse.
as a very, very general rule, an outsider coming into your family and fucking up the dynamics is doing it to destroy your family. i would say in the current environment the two main reasons for this are a) the cuck scenario: someone (a rival lover or a snake cult or something) wants to take your spouse and children for their own, b) the apoptosis scenario: the state has decided that society and maybe you would better if your family were destroyed and is undertaking efforts to do so
it is evident that having some innate resistance to people coming in and fucking your fucked up dynamic some more is adaptive in a world filled with cuckoos and apoptosis induction factors
it is also evident that society works by having people work out family dynamics on a bigger scale