Question, what would you call a creature that has horns and red skin, lives in hell where they torture sinners, and is variously portrayed either as flesh-and-blood monsters or ethereal evil spirits?
I dunno why people ever translated Oni as Ogres because they way more obviously correspond to Western depictions of demons in my view.
Because that's neither their original nor their major mythological aspect? Shuten-dōji, a strong runner for the single most famous specimen, for example was certainly always considered a very concretely earthly creature, while the Momotaro tale basically depicts them as a tribe of ersatz Viking raiders on an island. The whole "warden of Hell" business was a cheerful syncretism with Hindu-Buddhist ideas - the Shinto concept of afterlife is rather different and more akin to the ancient Greek realm of Hades, near as I know.
I'd also point out that oni were always depicted as highly variable in coloration (take the well-known "Red Oni and Blue Oni" tale for ex) whereas the whole "red horned dude with pitchfork" image of Christian demons is a very recent dumb stereotypization; you sure as shit don't find it for example in Bosch's famous hellscape (painted sometime between 1490-1510), Dante's Divine Comedy (written 1308-1320) or the numerous grimoires of demonology penned by occultists over the centuries.