I was thinking the same thing. Folks see birds and go "OH pretty!" then they get them and discover they're loud, messy, destructive and require gobs of work.
So they abuse and neglect them. Or if they're humane, put them in a rescue.
~~sigh~~
This is a major problem right now with parrots of all sizes. Pet stores and bird breeders sell babies which are lovable and compliant. But when the bird reaches sexual maturity after a few months or years, depending upon the bird, they start screaming, lunging and biting --all of which they're supposed to do because they're still wild animals and like you say, people will hit the cages, or the birds themselves, or squirt them with water, or they'll stuff the bird in a dark closet, dank basement, or cold garage.
Bird rescues are bursting at the seams trying to take care of all the cast-off parrots, like this lady has been doing for the last 20 years or so.
Pretty, pretty, pretty, pretty, pretty, pretty, pretty...
Oh, that's what he was talking about!