Chapter 526: Additional Chapter: The Tale Of Mjolnir's Theft (Part 2)

Mjolnir wasn't just important to Thor, but to the entirety of Asgard as well. Thor had used the hammer to protect Asgard on countless occasions and thus by losing the hammer, it was like losing a layer of protection for themselves. It was for this reason, all of the gods chipped in to help him in disguising him as a woman. 

Freya handed her clothes to Thor while the other goddesses bathed him with perfume and braided his hair to look like that of Freya. Even Loki chipped in and using his magic got rid of Thor's bushy beard, the one thing he had been proud of. Along with giving him a feminine look as a whole.

Having been treated like that, while hearing the goddesses and their attendants giggle as they dressed him up was the final straw to his patience. It was at that moment Thor made up his mind to eradicate the giants for putting him through this humiliation.