And as for this particular guy, he sounds like the exact sort of fellow who doesn't really consider anything about getting what he wants, now. Not future consequences. He didn't think of her as a real person, just a tool; he probably doesn't think about the rest of the Olympians even that much.
Also, I believe there have been a
list of rapes happening in Greek Mythology, some performed by Zeus, Poseidon, Hades, etc. He could have just figured that if the Greek Gods did things like that, then it was okay to do it to a Muse of Greek mythology.
If Zeus or Hades do get enraged at this, I wouldn't be surprised if they were more upset at her being
imprisoned than being raped, or that it was a mortal who did it to her, or that she had been traded for a trichonobezoar (which basically means that Madoc had bought her as a slave). Or at least that's what they'd say.
Zeus: Oh, that is just unforgivable. I mean, sure,
I may have committed adultery a few times and raped a few women... but I never kidnapped them for more than a week at most. And I always made sure to transform into an animal of some kind when I did it. Or a satyr. Satyrs are a type of animal. It's not rape when it's an animal doing it, it's just them being friendly.
Hades: Yeah... and my thing with Persephone. That's totally okay too because... um... she ate six pomegranate seeds and those are sacred in the Underworld. Yeah, you can't eat underworld food and leave so... she just had to become my wife even if she didn't want to. Don't ask about the kidnapping before that. That... that has a totally valid excuse I haven't made up yet.
Poseidon: What can I say. I'm a monster. Doesn't make it okay for guys like him to do that kind of stuff. *takes a swig of wine* It just means I'm rich and powerful enough to avoid the consequences. You wanna do sick and depraved stuff to people who can't fight back? Then be born a God or something. Poseidon out!
Hera: ... This is why I don't want modern humans worshiping us.