We should teach both kids and adults what constitute healthy interactions in this context and what to look out for; but the broad concept of a supportive relationship between a child and an unrelated adult should not in and of itself be taboo.
I suspect the nuclearizing of child rearing (possibly as a result or consequence of the Stranger Danger moral panic of the 80s) has created generations who don’t know what healthy vs unhealthy interactions actually look like so everything feels like it could be weird.
I feel too, like it's rare now to even see the sort of older adult being active with younger adults as a positive thing, even though it's the core of good mentorship. I've been blessed as an artist to have a lot of positive experiences and direction come from my artist elders.
A cpl of young girls used to live in my neighborhood. They would ride by my house & ask me questions about my hair, my dog, etc. One started coming by alone at times & would hang out with my dog & chat at me. Home life wasn't great (not abusive, just not ideal) I gathered.