it's an interesting take, the idea of just instantly doubling a population. i don't necessarily think it's evil, just short sighted. on one hand, he's giving life back to trillions... i mean, it's not just earth he brought back... let's ignore all the ecological fallout that would be guaranteed from doubling ALL LIVING CREATURES, not just people. for as many that have moved on and started new relationships, there's just as many that haven't. and again, we're not just talking about couples, but fathers, mothers, children, siblings. he's restoring all that.
on the other hand, stark didn't do it for them. i mean we all want to say that he's grown and is so much less selfish than he was when we met him, and he is. he's grown so much. but he didn't restore balance to restore balance. he did it to bring back peter and clear his own conscience (and stop thanos). he VERY specifically stated that he isn't losing what he got. he loves his daughter and is extremely selfish about her in the sense that he's not going to unmake her (though, as a parent who's gone through a terrible divorce, i'd never wish i was never married because my kids are FAAAAAR more important than my own suffering, so i get it).
but that leads to an interesting question as well... how many NEW kids were made during the 5 years? it definitely needs to be said that reverting the snap and subsequent 5 years would erase THOSE kids, too. BUT that wasn't stark's motive either, not directly anyway... it's pretty clear, i think that this is a fairly gray area morally... it was a completely selfish act, done selflessly.