The author seems to be a bit confused in their examples, as one guy in the comments said, they have a rather narrow idea of maturity, marking as bad even games that are over the top, but still powerful in their message, while putting as perfect example a game that might be mature, but its entertaining factor is very relative, even among adults.
Devil May Cry Forums
Innsmouth
I disagree about MGS in this article, yet I do agree many games trying to be mature by simple shoe-horning sex, swearing, and other stuff like this only to appear mature