I don't change my use of such words for other people, I do it mostly to change my own thinking. If others want to join me and also change their thinking that's also good.
"queer"?
It's called "sideloading" because you're sneakily installing software without the manufacturer's consent.
Remember it's never your device, you just have permission to use it.
I think "sideloading" is a completely ok term. it says what it is,, you load an app, not with the intended method (appstores) but from an alternative source, aside the official store. not a native English speaker, so I might not fully understand the possible connotations with this particular word, but I do not personally see anything wrong with it.