Clearly this is BS. Sideloading is perfectly safe if you just reputable resources.

What he’s really saying if that the average user is too dumb and will install any rubbish from anywhere. He’s not wrong but that shouldn’t prevent competent users from sideloading.

At least they’ve made the process scary enough that the average user don’t even bother to do it

It’s a non issue that shouldn’t be given any time.

I’ve sideloaded for years and never had any malware.