Except that there are:
https://en.wikipedia.org/wiki/Feral_parrot#Other
How many there are in absolute numbers I don't know, but your depiction of all parrots being too stupid to live in the wild is also incorrect. And other animals die too all of the time, so that is not a good assessment.
GP didn't say all parrots wouldn't survive - they said a majority wouldn't without a flock, which your link seems to at least partially agree with.
> And other animals die too all of the time
That’s exactly their point, the parrots are no different. The majority will die, which is what they said.