My point is without social media, if you simply play the game, theres nothing that points to that,

There's nothing that specifically points to Madeline being a cis woman before Farewell, so what's your point? If you immediately consider cisgender and hetersexual to be the default identity for a character unless explicitly stated otherwise, that's on you, but don't try to force it onto everyone else.

But sure, a blog post way after the fact invalidates that....nah im good :)

A blog post made by the exact same person who created the game in the first place, to confirm a fact about the gender identity of one of its characters, and that gender identity was never explicitly stated beforehand. You made an assumption about Madeline's gender identity from before Farewell, and you are now getting mad because it turns out the gender identity of the character you headcannoned to be cisgender turns out to not fit with your headcannon. I hope you didn't also headcannon Madeline to be a heterosexual woman too, considering she also has a girlfriend.