If the two individuals aged for a significant part of their lives together, offsprings are not the only “harm”.
Forming relationships with people that are different (as in, not relatives) helps avoid the bad parts of the family structure (the weird beliefs, opinions, behaviours, etc, that are taught within a family but are not accepted outside of it).
Without that, you can end up with something that seems like “cultural inbreeding” where the weirdness persists and grows, until it reaches weird shit.
On a side note
Arguably a similar effect already happens in western countries thanks to xenophobia, and that’s why you have people that care so much about transmitting their DNA and having their own biological kids as if it mattered. This is just the remnants of a deeply racist culture that believes that you need to preserve your family line, and with it, your DNA.
If people were mixing more with other cultures and origins, this would seem much more absurd.
If the two individuals aged for a significant part of their lives together, offsprings are not the only “harm”.
Forming relationships with people that are different (as in, not relatives) helps avoid the bad parts of the family structure (the weird beliefs, opinions, behaviours, etc, that are taught within a family but are not accepted outside of it). Without that, you can end up with something that seems like “cultural inbreeding” where the weirdness persists and grows, until it reaches weird shit.
On a side note
Arguably a similar effect already happens in western countries thanks to xenophobia, and that’s why you have people that care so much about transmitting their DNA and having their own biological kids as if it mattered. This is just the remnants of a deeply racist culture that believes that you need to preserve your family line, and with it, your DNA. If people were mixing more with other cultures and origins, this would seem much more absurd.
That is an argument from utility, which can most certainly be debated. What constitutes “bad”? That is a subjective interpretation.
And how do we define “weird shit”? Are “normal” relationships not “weird shit” and don’t they lead to “weird shit”?
Well, it matters to them. Therefore, it matters. Doesn’t it? It does to them.
Genuinely just poking at arguments here, I have no decided opinion either way.