It has more to do with the Bayesian weighting that IMDb wisely uses. It's actually a very good thing. If a game doesn't get enough votes there is no way for it to make the list.
Super Marios Bros. has a 9.1 rating, but only 3,848 votes. Meanwhile, the
Tomb Raider game that made the bottom of the list only scored an 8.9, but had 12,139 votes. You can see how this mathematical weighting affects movies/games more steeply the fewer votes they have. There's a standard deviation affect. You can see this easily in my thread from earlier this week:
The Best New TV of 2017 & 2018?
If you go to the show's actual IMDb pages you'll notice the shows with a really small number of votes have higher scores on their IMDb page. But I'm not quoting their raw score. I'm quoting their weighted score (as it is ranked in the "Top 250 TV" or "Top 250 Movies" lists).
IMDb is still highly useful, and a genuine voice of the people. Rottentomatoes and Metacritic are industry marketing, now. They're horseshit.