Is there anything more thoroughly vanilla than “rape fantasies?”

No.  There’s nothing more vanilla.  Or, really, less kinky.

You’re not a “Dom” or a “Sub” just because you get off on fantasizing or roleplaying it.  It’s as vanilla as “roleplaying” Ravel’s Bolero on motel satin sheets.  It’s as “kinky” as a French maid costume.  It’s as cis/het tapioca-bland vanilla as a Danielle Steele novel.

It’s not bad if you get off on it* mind you. Any more than if you get off on “naughty [xyz] girl” Halloween costumes, Ravel, satin sheets, or Danielle Steele.  Nothing wrong with vanilla!  But like those other things it’s still utterly vanilla.

And as a matter of fact yes, I’d stand by my assertion even if I switched to decaf.

[* Unnecessarily necessary note: If you can’t tell the difference between fantasy and consenting-adult roleplay from criminal assault then you’re a danger to yourself, your partners, your community, and society.]