I would claim that unconditional love in relationships and family is one of the pillars of civilization; there is also ample evidence that there is a natural neurological predisposition in humans towards such forms of love.

https://en.wikipedia.org/wiki/Unconditional_love

The problem is that it tends to be untenable at scale, it also requires reason as a counter-balance when one member of your family is abusive. Which is why unconditional love for country/nation is usually destructive (see nationalism).