Video games are products. If a game is difficult to the point that it is painful to most gamers, that is a problem with it.
I love the souls games, they're my absolute favorite. But they're not for everyone. Some reviewers it will click with. Others it will not. If a review score is, for that site, supposed to represent a value in which a general consumer can decide whether or not a game is worth buying, (which is a wide spread usage of the review score) then I can understand the game getting a slightly lower score.
I think one of the reasons the souls games didn't hit the 95+ score mark is because of that. They are certainly games that are of equal quality to games like Half-life 2, or OoT imo.
I think a few reviewers even mentioned that in their reviews.