You measure the size of a game by the number of ratings? I know a Steam game with several thousand reviews that has a single digit review number on Itch and not a single comment.
But should we upvote games just because they are small? Would that not skew the ratings even further? A game with 3 pity 5star votes looking "good" but is actually crap? Or at least crap for the special interest group it tries to appeal to. Like a horror game not being horrible (pun intended).
Based on my observations people downvote for two reasons. They hate a topic. Like AI as a prominent example. Or they were disappointed. The game promised something and built up expectations that were not fulfilled. Occasionally you might have one of those regular raters who really rate just everything according to their own rulebook. But most people do not rate at all. Or they only rate positive like you recommend.