That's another controversial thing with some of them that really shouldn't be, because like you said who wouldn't want their kids to have that advantage if they could?
There is also a ton of misinformation spread around about cochlear implants, for instance, they leave a giant scar (they don't and didn't even leave that big a scar when the technology was brand new in the 1980's IIRC.)
They made a movie somewhat recently, I haven't watched it but I remember seeing the trailer. It's about a rock musician that starts going deaf.
From people who have watched it, I've heard it's full of lies and nonsense about cochlear implants, including the lie about them leaving huge scars, despite the movie taking place in somewhat recent times.
It's just a really gross attitude they have. I can't imagine denying my children something that would open up entire new experiences to them.
Could you imagine if there was some surgery that would make your kid walk again, but you convinced them not to have it because you can't walk either and you don't want them to do something you can't do?
People would think you're a monster. This isn't that different imo.