The bias in the model took years to craft. Probably hundreds of engineers over many years built the system that crafted the data sets required to do censorship.
In concrete terms, what exactly could Google have hoped to gain from releasing an image generator that defaults to black Vikings? If it wasn't a mistake, what is the grand plan that it contributes to? And why has Google immediately about-faced and abandoned this plan? Did they think everyone would love the black Vikings?
In any case, the entire premise of this confected outrage (that AIs should be expected to produce historically accurate images for arbitrary inputs) is completely daft.