If oathbreaking is so reviled than why aren’t people like Cole and Daemon Blackfyre hated more? But made holy oaths to their kings and then betrayed without a justification. Aerys murdered people.

Criston Cole is despised. 

But Daemon Blackfyre is different – firstly, he had public justifications for his actions – justifications that half of Westeros agreed with. Secondly, he conducted himself impeccably according to the canons of knighthood and died gloriously, whereas Cole went out like a chump. Thirdly, Daemon wasn’t a member of the Kingsguard.