I think a small part of it is how Kojima looked at the translation given the original game, the hard work the translator put in keeping the flavour, feel and flow of the dialogue...As someone who has seen the rest of Kojima's work I have to say that Twin Snakes was his apology for how limited he was by the technology he had to make MGS. And my explanation for all the derision and snarky hatred for it... GameCube hate. It was an exclusive, PS 2 people were butthurt and invented a petty reason to turn their nose up at it and it caught on.
And got UPSET that the translator had 'changed' things and insisted on a 'more accurate' translation that ended up being worse than the original.