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While nature may not care about the emotional well-being of older people, or anybody really, children certainly do care about the emotional well-being of the older people in charge of raising them, though they probably wouldn't put it quite that way. They just feel anxious, upset and guilty when the people they count on most fall apart or lash out.
Your comments reference a golden age that never existed, a paper-thin surface version of a community where conformity ruled. While you personally may not have had "to contend with troubled, angry parents" many, or even most, of your peers certainly did. Their parents may not have verbalized these feelings and may have instead simply channeled those feelings into alcoholism, domestic violence, depression, etc. Your generation was clearly so lucky not to have heard about the problems, instead simply having to deal with the side-effects.
As for your ridiculous comments about gay parents, how would gay marriage make the problem of confusing extended family relationships any worse? We could do away with the awkward "partner" label once and for all. Why are gay parents responsible for changing your laughably outdated "stereotype"? Your "chartreuse pants and black polka-dot shirts" characters conjure images of self-obsessed suburban house-wives far quicker than anything else. Why don't you go meet a few gay couples raising children before you pontificate again.
Parental narcissism is obviously undesirable, but it pops up in many diverse ways, in gay and straight parents, in permanently monogamous pairings and in fragmented-by-divorce family trees. Simply proscribing a "shut-up and be unhappy" approach to parenting is not going to help anyone.