Simply reading FAQ will shows they are not a store, quoting:
At the same time, backers must understand that Kickstarter is not a store. When you back a project, you’re helping to create something new — not ordering something that already exists.
you might think they are( a store ), but that doesn't make it true.
It doesn't matter what Kickstarter FAQ says, a judge need to decide once and for all what Kickstarter really is and how can its customers defend themself against fraud and scams like Triggertrap. "I was an idiot who didn't know what he is doing" is never an excuse when you take other people's money and you promise them something.
Now it seems to explicitly refer to returning remaining funds. ("they offer to return any remaining funds to backers who have not received their reward (in proportion to the amounts pledged), or else explain how those funds will be used to complete the project in some alternate form.)"
Kickstarter has been tiptoeing this line forever between Not-a-store and Not-giving-people-what-they-paid-for-is-a-very-bad-thing.
https://www.kickstarter.com/projects/triggertrap/triggertrap...
I understand Kickstarter wanting to keep the pressure on project creators while minimizing the perceived risk in the eyes of funders, but the current TOS seems to mirror the reality much better than the old one. (Threats of lawsuits and so forth notwithstanding.)
EDIT: Ah. This seems to have happened last fall: http://arstechnica.com/business/2014/09/kickstarter-tries-to...
If no one has sued Kickstarter, that may mean that Kickstarters has been successful at direct responsibility to projects rather than Kickstarter itself.