Comment by fauigerzigerk

True, but on the other hand the meaning of words often follows usage rather than the other way around.

There is no choice of words that will make it normal to install mobile apps from anywhere other than an app store. Whatever word we use will take on the meaning of doing something unusual.

"Sideloading" doesn't have an inherent or deeply ingrained negative connotation. I don't see a reason to try to change it.