While I agree with your overall argument, Outlander's depiction of rape is very different from porn's depiction of rape.

Outlander depicts rape as a horrific, traumatising event that leaves lasting scars on victims' minds. It's the opposite of titillating. It's stomach churning.

Whereas porn that uses rape as a fetish, depicts it in a titillating way.

That said I would say Outlander definitely has softcore porn in it, and that's why I love it. All the sex scenes between Jamie and Claire are very arousing to me lol.