Pretty much.

[The real reason is slightly more specific, but Asriel likes to think he's smart enough now not to get into the whole soul thing that the humans were most afraid of with...a random human he just met. It boils down to the same thing anyway; it's not like anybody ever did take a soul back then.]

I've had a few human friends, though. Sometimes one falls into the Underground, and then they're stuck in there with us.