It's not what it will do to evolution, it's what has already been done to evolution. This sort of non-conformist, spiteful genetic mutation has always occurred, but historically they have not reproduced because failure to conform with the herd or be cooperative was not conducive to making babies. Thanks to socialised healthcare and schooling and lower mortality, undesirable genes are able to reproduce and spread. The damage to Darwinian selection was done a long time ago when we stopped letting the unfit fail and die. What we see today is the result of that, not the beginning.