"Private" and "incognito" mode are fundamentally misnamed. They provide almost no real privacy wrt counterparties over the network, just to other people using the same computer after you.

Amnesiac mode, if you will.

I remember upon introduction, tech news would jokingly refer to it as the porn button if they were immature enough (and let's face it, back then most of us and the web news sites were quite literally immature). Sounds like that would be more accurate, but it fell out of style and now we have this name :(