I don't think anybody is arguing that the Kinect is useless. It seems to be just that people don't want to be forced to either use a Kinect or not be able to run their console at all. There's a couple good reasons for this:

1) It's another thing you need to stick on top of your TV setup, which can cause problems with some setups (e.g. flat screens)
2) It's an always-on camera and microphone sitting in your living room watching you game. It's pretty reasonable for people to be wary of that whether you personally are or not.
3) Microsoft's statement was that they wanted the Kinect to be necessary to game developers could assume the Kinect will be on every platform, and not have to worry about alienating potential customers due to hardware restrictions. This alone is an issue because now developers are inclined to do all sorts of unnecessary things with the Kinect.

All 3 of those things would be issues for me. I get that the target audience of the Xbox One wasn't just the hardcore demographic, and that a lot of people would love more "hands-free" Kinect games. I'm super excited to see what kind of new game play mechanics arise from the inclusion of the Kinect with every system. I just don't want to see it get involved in titles that it shouldn't be involved in, such as waving your hands to reload a gun or something. #3 is still sort of, kind of an issue since the Kinect is still included with the Xbox One, but I'd assume developers would take note of the public's preference to have it be optional and develop accordingly (i.e. be less inclined to needlessly use the Kinect).


tl;dr I want to see what new games and game play arises with the Kinect. I just don't want it ruining titles that don't need it, and I want the option to disable it if I'm not using it (which I already have). I think the majority of the people are arguing something similar.