Who the fuck does that? People will praise the themes that MGS2 posits, but no one takes it as seriously as you are saying. Kojima himself hardly takes it seriously, that doesn't mean that he doesn't bring up some very serious real world questions and philosophy into his games. You know how much supplemental reading and research i've done in reference to real world history thanks to kojima's games? More than any other game ever, and thats a damn fact.
If somebody played Assassin's Creed Unity and then decided to go do a bunch of reading on the French Revolution I'd think that is nice, but it wouldn't really change my opinion on the game or its narrative.
The games themselves are full of goofball bits, but from all the long-winded codec philosophizing and overwrought trailers I think it's clear that Kojima does take a lot of this stuff pretty seriously. The series' complete inconsistency of tone is part of why I say this would never work in any other medium. There's no scene in Schindler's List where Oskar Schindler hides in a locker and masturbates to a picture of a woman in a bikini.