My dd is nearly 14. She isn't aware of the fact she's meant to be broken, or irrevocably damaged, and instead is happy, well adjusted and thriving. More so than many couples dc. Then again, we tend to form our views on fact, rather than stereotypes, and are both intelligent enough to interpret statistics correctly, rather than take them at face value.
I could also share lots of anecdotes about the damaged dc of naice couples, but just like the lone parents anecdotes, they hardly represent the majority.
Dd wasn't donor conceived, but might as well have been. If I'd ever seriously considered another, then I would have gone the donor route.
Practically it is harder, but as I've nothing to compare it to I have the reversed perspective that it must just be easy with two parents. Also hard because a minority of people have some ignorant opinions on single parents. They expect you and your dc to be less worthy/ objects of pity, and ime get really narked if you actually do as well, or better than them. If you can manage the practical side and are mentally tough, then no reason why not to just because you are single.
As to ideal families, imo it's like eugenics. Nobody sane believes only intelligent, attractive healthy people should have kids, and I don't see that having two parents and four grandparents is a prerequisite to reproducing either.