Author here. I admit I am rather startled by the tone of many comments here and the accusations of disingenuity. Splitting hairs about the origin of the term "sideload" does not change the fact that those who promote the term tend to do so in order to make it feel deviant and hacker-ish. You don't "sideload" software on your Linux, Windows, or macOS computer: you install it. You have the right to install whatever you…
1. Laptop
2. Phone
3. Car
4. Washing machine
5. Handheld GPS
6. E-reader
7. TV
Is there some intrinsic different between a device where the manufacturer has programmed it using an ARM/x86-based chip vs a microcontroller vs some other method that means in the 1st case I have the right to install whatever I want? Because that feels like what's happened with cell phones: manufacturers started building them with more capable and powerful components to drive the features they wanted to include, and because those components overlapped what we'd seen in desktop computers, we've decided that we have an intrinsic right to treat them like we historically treated those computers.