You try to equate "most recent" on Itch with "sort by release date" on Steam. But there is no such thing as an official release date on Itch you could sort by.
You keep saying that, and I keep saying that it would make perfect sense to sort by time of indexing. This time is when a game is "released" for the public for the purposes of discoverability on Itch, since it's not discoverable before this time, and is discoverable after this time. If it's sorted by time of indexing, each game would start its time on the Most Recent page at the top (for however short a time), just as one would expect.
The default list has every release status in it.
But I'm not talking about release status. I'm talking about indexed vs not indexed, and the Most Recent list only has indexed games in it, while it does not have non-indexed games in it.
Discussing about the expectation from a list called "Most Recent" is interesting, but the term is ambigous. Whom is it most recent to? From developer's perspective, or Itch's, or the user's?
From the perspective of the Most Recent list itself, with Most Recent meaning the most recent game to be included on the list. There is nothing ambiguous about that.