It's not so much the fact that they have DLC or that said DLC is expensive, it has to do with the way they shelled it out for the first game. First they say that unlocking Chaos as a playable faction would be a pre-order exclusive bonus. Which, already, is enough to piss off people looking at an $80 game and caused a bit of a split in the community.
Then the game launched, and the very week after launch they come out and say that you can buy the DLC to unlock Chaos, now suddenly shitting on the people who did shell out a lot of money sight-unseen so they could have the "exclusive" unlock. Didn't help that the original price for the DLC was something like $20 on top of the already hugely expensive title.
But then a little while later, people said "hey, for a Warhammer game, there doesn't seem to be any blood getting spilled", and they got the response that production had been a bit rushed, so it couldn't make 1.0.
And then blood graphics came out... As a $9.99 DLC. At this point people just said "alright, fuck you Mr. Scrooge" and boycotted the game because supporting that kind of behavior is fucking abhorrent. Then beastmen came out as another $20 add-on, but by that time the lines were already drawn.
So you see, it's not about the specific DLCs or however much they may cost, it's about telling the industry that those practices are unacceptable.
(This was all for TW:W1, mind. The second game just gets shit by virtue of association)
Um, a lot of this rant is just flat out wrong. For one thing, blood dlc have been a thing in total war games since Shogun 2 (to keep the game's rating down), and it doesn't cost $10, it cost $3.
Secondly, the whole preorder chaos dlc thing was scummy, but you've made it several orders of magnitude worse somehow. Chaos was never an "exclusive" unlock bonus for preordering the game, and you didn't have to pay extra. You paid $60 (the base price of the game, not $80) to own the game before it launched, and you got the DLC for free. Then because there was a massive backlash against that, because it was scummy, they changed it so that if you bought the game in the first week you got the chaos dlc for free as well. They never planned to have it just be pre-order content, they made it clear form the beginning it was going to be a paid DLC, and you din't have to pay anything extra to get it.
Is Day 1 DLC scummy? Sure, but first of all, the game is good enough without Chaos being a playable faction, so if you don't want the DLC, you don't need it, and secondly, they seemed to have learned from the backlash since the bonus for preordering Total Warhammer II was that you got free DLC for the first game.