Sexist manbabies have made a point to brigade this game because they can try to hide behind the 'realism' argument. Nobody cared when CoD put in women. That game sold like hotcakes.
If nobody cared about female soldiers in CoD:WWII, doesn't that contradict your "sexist" accusation and suggest that something else is going on?
I think that this controversy didn't happen when Sledgehammer added women (and even black Nazis) in CoD:WWII because they didn't make a big deal out of it. In fact, they purposely left
out playable female characters from the single-player campaign and even the multiplayer trailer featured all males, even though the actual multiplayer mode supported female characters. Sledgehammer actually showed a lot of respect toward people who wanted a game that looked and felt like WWII while not totally leaving out the other gender and skin colors.
In contrast, DICE chose to make a conspicuously female soldier the focal point of the very first glimpse of the game that people saw and even chose a similar looking actress for the still image for the trailer and game posters. That helped to make a first impression on a lot of folks that the game was not very WWII-like. It wasn't just the fact that the soldier was female, either, but that she didn't look like a 1940s female, she had a mechanical arm, there were male soldiers who looked anachronistic, as well, and the events and circumstances featured seemed outlandishly unrealistic. All of those things received flak, but the female was the easiest to single out, because it was the most conspicuous and suggestive. In contrast, go watch the CoD:WWII trailers and you'll be struck by how familiar and honest toward the actual conflict that they seem. For example, the soldiers wear period-appropriate attire and all look alike, the circumstances (like the beach landing) look like those out of WWII movies and the action isn't so unrealistically chaotic.
Basically, Sledgehammer skillfully designed and marketed their game to appeal to history fans while still being inclusive, and the reward was the game selling like hotcakes. DICE, on the other hand, really screwed up by prioritizing micro-transactions, then initiating their marketing by playing up that and the inclusion aspect, rather than the historical angle, and then compounding the issue with their excuses and accusations. That's why fans are upset. If DICE had done what Sledgehammer did and built their marketing around the war, itself, and only slipped in females without making a big deal out of it, they could've avoided most of this negative reaction and the possibility that it'll hurt sales.
To see what I mean about the reveal trailers for both games, watch them again and see if (even character gender aside) one strikes you as looking more like WWII to you than the other.