Because the game looks nothing like the concept art that sold everyone and, instead, plays as boring as it looks.
For 4 million I don't think expectation were too high, some devs also debunked the nonsense some people spread about how it could have never looked close the concept art for that money. And them spreading themselves too thin with 3ds and Vita is not on us, bad stretchgoal planning.
As for my personal expectation I thought someone with Inafune's pedigree/name would care enough to at least value good communication with the backers. If that would have been there I would be more kind, game development is hard I can empathize somewhat.
Instead radio silence and questionable things happening around Red Ash.
In that sense I feel very justified in being quite salty and harsh.
Also fairly sure that the story elements will suck and be annoying(judging by the backer demo). Money spend in the wrong places. Meanwhile the Plague Knight story manages to be full of charm without overlong cut scenes and voice acting.