I find the term "sideloading" funny. It seems artificially created to be a derogative phrasing for something which was and is completely normal and advantageous.

There was a time, when internet and computers weren't that old, where you would just visit a website to download and install a program.
It's still common on the desktop market. At least for Windows and Linux systems.

Google used the brilliant idea to chain users up to their own eco-system, by - very successfully - creating the illusion that using the Play Store and a tremendous amount of Google services and apps are the only way to go on Android devices. Apple does the same. Users aren't used to "the old ways" anymore like on PC for example. And while it might seem like a win-win situation for the company as well as for users (it is easy for most and auto-updates are nice), situations like these highlight how dangerous it can be to allow a company to have complete control over a market.

In other words:
Teach people how to download and install stuff from the web again!