I like to think critics and reviewers are part of the reason for this "culture of negativity." They tend to be the first ones to insult series as well as insult the people who like the series, even going as far as painting them as "the reason why the [blank] industry sucks the way it does. Like naturally COD is popular because people like COD games and buy them so usually reviewers imply or outright say that the COD fans are to blame for the domination COD has on the market and all the COD clones therein. Ergo, all COD fans are attacked. Thus creating a culture in which people want to screw over content they do not like by attacking what they believe is the source the people who like the things you don't like (thus buy it, generate revenue, makes it successful, etc.). People do not like you liking DMC because "it's not supposed to be liked" and your praised helped make what they don't like successful, so you are the enemy.
Inversely it's also a "put your money where your mouth is" type of deal. With all the bile and criticism critics tend to put out on games people actually do like and how they belittle the people who like them, naturally those people expect a title that completely blows the games they insulted out of the water. Something that is so good it justifies their previous negative reviews. It can't just be "good" or "fun" because those were the types of games, in their opinion, the reviewer shot down in the past, it has to be "completely perfect" or the critic paints a target and allows other people to "criticize" and "give their opinions" on the stuff they like.
Inversely it's also a "put your money where your mouth is" type of deal. With all the bile and criticism critics tend to put out on games people actually do like and how they belittle the people who like them, naturally those people expect a title that completely blows the games they insulted out of the water. Something that is so good it justifies their previous negative reviews. It can't just be "good" or "fun" because those were the types of games, in their opinion, the reviewer shot down in the past, it has to be "completely perfect" or the critic paints a target and allows other people to "criticize" and "give their opinions" on the stuff they like.