There's no such thing as trying to be objective. That's impossible. How do you try to judge objectively good gameplay?

By evaluating what the developer intended, if they succeeded, why or why not, and if it was enjoyable.

Have you seriously never heard a single reviewer praise a mechanic that “wasn’t for them”? Like, I don’t particularly love the ultra realism and slow pacing of ARMA, but if I were to review it, it would be completely amateur to list them as negatives since they are very clearly intentional facets of the game design.

However, if I found that gameplay mechanics of ARMA that were presumably intended to immerse the player in realism were backfiring and taking me out of the experience by glitching, I could say that this particular attempt at realism is a negative of the game because it wasn’t executed properly.

I’m sort of mind blown on what you seemingly perceive critics to be. “This is an RPG, but I don’t like those, so I don’t like this game”. Where the fuck are you finding reviews like this?