[ninkendo]

That's an extremely disingenuous statement. It's not just "a [huge] exception", it's the entire basis for google's strategy. AMP isn't just a standard for how to construct a website, it's a way for external entities like Google to host your site directly inside their site, so that they have ever-increasing access to your browsing behavior. Now Google doesn't just know what results you clicked on, but what links you're following inside those results, how long you stay on the pages, etc.

Facebook, twitter, reddit, etc already utilize similar techniques on their mobile apps to make it so "web links" you click just keep you in the app.

But the web (as in, not bespoke mobile apps, but what you get in a general-purpose web browser) is supposed to be decentralized and resistant to any one entity owning the end-to-end experience.

I'm aware that any other entity (like Bing for instance) could do the same thing that Google does, and that the AMP standard isn't what's at fault here, but there should be no doubt as to Google's motives.