A “demonstration” isn’t a negative “monstration,” a “demonization” isn’t a negative “monization,” a “delight” isn’t a negative “light” a “demarcation” isn’t a negative “marcation.”

“De” as a part of language isn’t universal in its usage. In the case of “denomination” it is used for dividing, rather than negating, just like “demarcation.”

Because (((they))) want us to forget what "Sola scriptura" is.

I always understood it to mean "not denominational"

The idea being that sects (denominations) are those which adhear to a particular view of the given religion. A "non-denominational" sect is one that does not subscribe to any one sects viewpoint excluively, but instead treats controversial topics with an agnostic eye.

I say "controversial" because this is how it manifests in most "non-denominational" churches/etc. The truly "hot button" shit is often treated as "we don't know, oh well, let's move on".