I'd understand if they were a random user, but a mod should already have at least some understanding about a community's topic.
But worse to me are their comments in that post calling the people responding "childish trolls in this community". I do not think that this is appropriate for a moderator.
I'm not seeing the "insulting users of the community" point you stated OP, could you clarify? I did see one snarky response to a dude calling him an asshole, and I also saw posts stating he shouldn't be a mod, and generally very hostile responsens. Those in mind, I think his output was quite civil even though I disagree with his reasoning and opinion to large degree.
This feels like a witchhunt to me, and I for one don't think a volunteer moderators job should be in question if he has a hot take on something. He's just keeping the spam etc. clean, he's allowed to have differing opinions on subjects, as long as there is no misuse of his mod powers.
That's honestly an unreasonable expectation of volunteers, and especially not one I'd want mods to measure themselves by. A mod who thinks he is better than the common users would be a massive asshole.