Features aren’t rights, if you want a phone that let’s you run whatever you want, buy one or make it yourself.
What you’re trying is to use the force of the state to make mandatory a feature that not only 99% users won’t use, it vastly increases the attack surface for most of them, specially the most vulnerable.
If anyone were trying to create a word that gives a “deviant” feel, they wouldn’t use “sideload”, and most people haven’t even heard the term. There’s a world of difference between words like “pirate”, “crack”, “hack” and “sideload”.
If anything I’d say it’s too nice of a term, since it easily hides for normies the fact that what you’re doing is loading untrusted code, and it’s your responsibility to audit it’s origin or contents (something even lot’s of devs don’t do).
If you want to reverse engineer your devices, all the power to you, but you don’t get to decide how others people’s devices work.