Kickstarter isn't meant for customers. Its meant for people to invest in something and possibly seeing something in return. The only difference is that instead of seeing money, you'll actually obtain the product (and other bonuses) instead. Which is pretty much the same thing.
You aren't making the company's job any easier. They still actually have to bust off their asses to do the actual work. Its just investing the funds to see the job through. The problem is people still like to say "I'm a consumer" because they have invested in receiving the actual product. They aren't. They are an investor.
It isn't about "hey, you can make one, you don't need me", its seeing if there is an actual market for your product. If you manage to break even on your goal for funds, then you theoretically expect that the project can be profitable afterwards. Putting a game (or anything for that matter) out there and there isn't a market is not only bad business, but for a company can kill it.
If you don't want to invest in something, don't. Let others take the risks and you just buy it when/if it comes out. When its actually a product and you purchase it, then you are in fact a consumer and have the full luxuries that come with being one.
There are more egregious examples than Harmonix. Amplitude failed the moment they said it would be on the PS4 only. The console was/is still young, therefore it limited the possible investors and it alienated the investors who were on other systems. If this had been done a little later in the PS4's life, when the number of investors would've been quite higher.
Also, you are mistaken with Double Fine and Broken Age. They split Broken Age into 2 parts so that 1, people who made the investments would have something they could have in the mean time. It would also allow Double Fine to produce sales from people who didn't invest in the game, and turn those sales into extra production money for Part 2. This was seen as a better solution than start destroying parts of the game that had been promised to the original investors.
Does it excuse the screw up? No. However, they at least found an alternative to saying "nope, we entirely fucked up. No game now". Which could've been a very real possibility.
