Is that a good thing or a bad thing, Emmanuel? I didn't mean to out you! :)
I'm trying to keep an open mind, and I'm eager to see what others think about it. I totally get why you don't want negative-leaning terms, but it still make sense to me to "Mark all except Included Entries" - I guess because that is literally what I have been doing over and over for so long now, more frequently than just marking a few entries. It's truly a "mass" operation most of the time I'm using it, so my brain is stuck on the "all except" part.
At the end of the day, I'll be excited and grateful to have the feature, even if the menu option says, "You figure it out" LOL! :)