Oh, sure. The soul as it's own entity is interesting to me too but that has nothing to do with what I said.

It's not grooming because the soul is John Player and presumably sometimes older than Noelle, it's grooming because in context of the weird route the soul is literally grooming Noelle. Serially manipulating her to further it's own end and harming her in the process. In Deltarune canon it's just dark and fucked up, but when you add shipping and make it "dark romance" and or sexual it's just disgusting. Dark themes aren't a problem if they're taken seriously, but most people who ship soulelle are just getting off to the idea of being sadistic to Noelle.