That's a bit simplistic explanation. Even if Ashley agrees to go to the drug dealer, she is doing it to protect her friend, so the ensuing sex is still non-consensual (coerced). Regardless of the writing that defines a bit of self-degradation preference which triggers a sexual response, the act itself is non-consensual because, if there were some other way to protect her friend she would choose it.
Again, the game is multi-layered enough that every choice can be viewed from different perspectives. Some see Ashley agreeing to go to the drug dealer as consensual and point to her sexual response as evidence. I see it as non-consensual and say the sexual response is self-revelatory about desires she previously was not aware she had.
Either perspective is fine and true. And, of course, that's what makes this game so engaging.