While misleading may be a bit strong, and I can definitely understand feeling it being uncalled for, there is an actual expectation/culture mismatch here.
You seem to be hewing closer to the original semver convention, with major version 1 being the first public release, ergo the first release being v1.0.0 is completely correct.
Meanwhile, people here tend to be used to versioning conventions similar to what is used by many patreon games, which resembles how Steam early access games treat versions - 1.0 is the official launch version, more or less feature-complete and hopefully not too buggy, though of course expansions and reworks (and reworks of reworks; hi Stellaris!) may follow. The versions during the development up to that full release are v0.something.
You will get quite a few people that see v1 and assume that this game is more or less complete, some of them will miss the cues from the gamepage, and some of those will even click through the disclaimer ignoring it or get upset. You can definitely say that's not your problem, but it is what is is.
Anyway, I tried the first version and while yeah, it does need polish, it has a lot of potential
(And yeah, that content being outsourced to unofficial official (or official unofficial?

) mods is sadly a necessary workaround in the face of the paypro bullshit)