Wouldn't it be accurate to say that you can no longer install apps on your phone, only Google can?

If we're being pedantic, the user still has to perform the final action before the install begins. I think it' more "Google has to allow you to install apps on your phone"

And they've never allowed the users to uninstall certain apps.

(interestingly the keyboard app is not among these, so my sister has uninstalled it by mistake once)

You mean "Google has to perform final action after user petitions it to install"

(not really final, Google can uninstall your apps anytime if they are deemed undesirable)

I'm not suggesting a drop-in replacement within that context, just that widening the definition of sideloading does us no favours

'installing from beyond the walled garden' would be a nice fit here imo

extramuraloading?

Installing is still the right word, you just need to use more of them:

"Installing arbitrary packages"

vs

"Installing google-approved packages"

> but "banning installing" wouldn't have been correct here.

it would

and it would show exactly why it is absurd

But currently, the masses know it only as a button in the play store and app store.

Freestalling?

"Freely installing"?

"banning installing from anywhere but play store"