This is what they say in their blog post:

You will continue to be able to build and run an app even if your identity is not verified. Android Studio is unaffected because deployments performed with adb, which Android Studio uses behind the scenes to push builds to devices, is unaffected. You can continue to develop, debug, and test your app locally by deploying to both emulators and physical devices, just as you do now.

If you see a loophole in the clear argument they're making there, I'd love to know. I don't see any obvious ones.

I'm just not sure people have been referring to that method when saying 'sideloading' and Google didn't mention sideloading specifically there.

This is what they say in the quote this article is about:

"Does this mean sideloading is going away on Android?

Absolutely not. Sideloading is fundamental to Android and it is not going away. Our new developer identity requirements are designed to protect users and developers from bad actors, not to limit choice. We want to make sure that if you download an app, it’s truly from the developer it claims to be published from, regardless of where you get the app. Verified developers will have the same freedom to distribute their apps directly to users through sideloading or through any app store they prefer."

In this paragraph they don't mention ABD at all similar to how in your paragraph they don't mention sideloading.