They're defending fictional non-con. Not real rape. And they're one individual. I don't agree with them. Rape, even in fiction, makes me uneasy. I wrote a noncon fic for drama once, and people thought it was hot. It made me so goddamn uneasy.
1. They commissioned someone to write a heterosexual Heavy/Pauling fic long before she was outed as gay. The person is merely filling out their commission.
2. She's just a fictional character. They all are. Medic's canonically possibly with a woman, and so is Heavy, and every fic I've read consistently portrays them as 100% gay, and repulsed by the idea of sex with a woman.
3. It's great to have shows with more diversity and so on, and I support it, but at the end of the day, none of this shit actually affects the real world. At all. Ever. No amount of gay porn or trans headcanons stops trans people from being brutally murdered, or gay people from being disowned by their families. That's the kind of shit that actually affects the real world.
4. Valve are such pathological liars that it's a good chance she's heterosexual. They deliberately say things to piss people off and give them false hope.