Having a wife and kid(s) is a normal part of society. It's how we survive as a species.
Contrary to popular belief, homosexuality is not the norm.
Whilst these MGS games feature bisexual characters, their sexuality does not dictate their personality.
Being lesbian is also a normal part of society. And no one is saying homosexuality is the norm. But it is normal and those people exist. Looking at Gears you have 3 heterosexual dudes and one lesbian woman in the squad. How do you somehow interpret that as homosexuality being "pushed" as the norm? Like I said, there is a major double standard in seeing a woman taking a polaroid of her girlfriend as "shoving sexuality down people's throats" while not batting an eye at the guy voicing worries about his wife and kids in the same scene. Heterosexuality is also a type of sexuality and it's "shoved down people's throats" on a daily basis in all forms of media if you want to look at it that way.
And again, how the hell does the sexuality of MGS characters not influence their personality? The codec discussion about Vamp literally says his code name, which I'd say is a huge part of his personality, is a reference to his sexual orientation and not his vampire-like qualities. He develops a very strong affection towards Fortune because she's the daughter of his male lover. Volgin literally sees through your disguise by fondling your junk. He gets confused and then mad at you if you put on the mask of his gay lover during the fight with him. Meaning his sexuality is even implemented from a gameplay perspective. In Peace Walker you also have Dr. Strangelove making it very obvious through dialogue that she's not into men and prefers women.
Like what are we doing here? A character literally named after his sexual orientation is ok and not "pushing it in your face" but a character whose sexuality is only hinted through 10 seconds of a cutscene with zero dialogue at is a bridge too far?