I think part of the problem is that there aren't that many good JRPGs frequenting western markets anymore, so there aren't many fans of the genre left. As a result, many of the journalists reviewing the games do not like the genre, and do not want to be reviewing them.
They usually do not finish the games either, which doesn't help matters especially on a game like this which I feel is kind of a slow burn, picking up later, but also making you appreciate the lightheartedness of the earlier moments of the game as things get much more dramatic later down the line. It's also easier to post a negative article if the franchise is unpopular, because no one is surprised. I have felt on many occasions, for games like Disgaea, journalists have not played the games extensively and have instead, simply referenced their old reviews on Disgaea games and mimicked a similar score.