Because Vonnegut made an affirmative claim that this doesn't hurt children, and the comment was challenging that claim. I didn't notice anyone making a claim that it definitely does hurt children.

Evidence is hard to untangle from other social factors. It is relatively safe to say that people have in the past not been sheltered from rough language and did just fine in most every culture. Sheltering children started about Victorian times I suppose, later than children got removed from dreary factory work in the generalized Western culture. (And incidentally later all kinds of work.)

So no, the onus of evidence is on people claiming that rough language hurts children in some way. (Note we're not talking about abusive language here.)

It's ok to say "it doesn't appear to" but the onus of evidence is always on someone making a positive claim. It's safe to say that children have historically not been sheltered from many things that are today definitively known to cause harm, so the appeal to the past is not a strong one here.

The positive claim being that coarse language hurts children, yes. This is the positive asserion that needs proof.

Nobody has made that claim in this thread. The positive claim we are discussing is still Vonneguts quote.

The question "Why damage children at all by choice?" rests on the implication that these things damage children, and avoiding them avoids damaging children.

I was quoting Kurt Vonnegut who affirmed it DOES damage children to some degree.

> don't damage children much

OK, but nothing in there implies that avoiding it guarantees no damage, or even less damage.