Please call it what it is and always has been:
I.N.S.T.A.L.L.I.N.G S.O.F.T.W.A.R.E
"side load" is like "jay walking'
seeks to stigmatize humans being human.I call it "direct install" personally, implying the play store is the indirect install.
When you jay walk you take the risk of being hit by a car, causing injuries to you, to the driver, and to other nearby people.
So I don't understand your analogy? Are you suggesting that pedestrians own the streets and should do what they please, as users own their phone and should have the right to do as they please? Or something else?
"Being able to install software is why was why I switched to Android"
This doesn't make sense to me. iOS and Android (and HarmonyOS) all allow you to "install software".