And if J. G. Quintel came out and said the friendship between Mordecai and Rigby represented LGBT love, would you bow down and praise him for his glowing interpretation?
What you're not understanding is that Sugar doesn't have the balls to come out and say that they're lesbians. Or even women. They're genderless space rocks, and that makes them super safe and instills plausible deniability.
"What's with this orgy of dykes raising a boy in this children's cartoon show?! This is unacceptable!"
"No, see, they're genderless, so they aren't lesbians. No, see, the fusing is to power up, it's not sexual. No, see, they shapeshift into what's convenient, they aren't fat and butch by nature."
Alright, that's a little harsh, but let's put it this way: gay people, who feel underrepresented in the media, who still feel discriminated against and looked down upon, some of whom actually fear for their lives because their families disown them and force them on the streets, haven't fought for years to get an "implication." If they're gay, have the balls to admit it or show it in some significant way besides "oh let's fuse ;)"
It's like when the only legitimate show of romantic affection between Korra and Asami, a hand hold, happened at the very last second of a four season show, and the creator wrote a blog sniffing his own ass about what a progressive man he was, actually using the words "hetero glasses" to describe anybody who didn't think it was real. And desperate fangirls bought it hook line and sinker and praise Bryke as those very progressives, despite it being literally the safest, easiest, laziest thing they could have done.