"I can't think of very many cases in which people endanger themselves or their reproductive chances for the sake of cute animals." A) Drivers swerving to avoid cats and bunnies etc. B) All the warnings about leaving bear cubs alone. I can think of non-cuteness explanations that probably cover some part of each but it seems idle to reject any role for cuteness in those survivability risks.

Mammals that bear many children less cute than a species that bears few: rats vs guinea pigs. But in any case it is very strange even to suppose that cuteness would be a universal aesthetic.