Elementary kids making moaning like sounds

Hey teachers, so I'm curious if this is a Gen alpha thing, but my son at second grade started making moaning noises. It's the most annoying and disgusting thing. Does it without even knowing, it's engrained in his brain. Wife has been to some school functions and she says she's heard kids make these noises.

Why the hell is this happening?!?! Young kids with unfettered access to Internet or those with older siblings and they hear/see things they shouldn't?

Thanks for your input.

Edit: wow I'm definitely not alone in this struggle. Thank you everyone for your info on this. I can't believe this is coming from online gaming as some of you have shared.