The suggestion is usually correct, though. Google does a terrible job of vetting Play Store apps, but they do still have some automated safety checks, and they kick out known malware once it's found.

If you allow sideloading, you give up all of that. It's still perfectly safe if you trust what you install, but you have to make that assessment. Google can't save you.

This is exactly how I wish iOS worked. It's also basically how the Mac works nowadays, except replace "App Store" with "Apple notary service."

How would you suggest Google correctly communicate the risk?