From what I've read, rape had no toleration under Viking law, but other sources I've seen make mention of slave-rape and of Vikings raping even their male enemies to humiliate them. And obviously, the idea of the uber-rapist/pillaging Viking has to have come from somewhere- so where?
What have you read that suggests rape was not tolerated? Viking morality is not too different from that of modern outlaw groups, such as Boko Haram. Rape was, like theft, an offense to the victim's family, personified in the honor of the male family head. It was not a crime against what we today would identify as the victim.
If you want to get a nuanced look at Viking morality (and how it was fundamentally different from our own), have a look at Ian Miller’s "Gift, Sale, Payment, Raid: Case Studies in the Negotiation and Classification of Exchange in Medieval Iceland."Speculum 61 (1986): 18-50. To see how it was different from the rules of conduct of contemporary peoples, have a look at Guy Halsall's ‘Playing by whose rules? A further look at Viking atrocity in the ninth century.’ Medieval History vol.2, no.2 (1992), pp.3-12.
I think that the problem here is that you or some one else have been confused about the difference betwen norse and vikings. When we talk about the people that lived in what we would now call scandinavia we call them norse. Vikings are a special name for norse raiders.
The norse had laws against rape, killing and theft in their own region/community, but when they went raiding they would have no problem killing, stealing or rapping.