Speaking personally, Kickstarter (and their ilk) has become more than just a fundraising tool, for many startups (like the bike light people, and the 3D printer pen, and so many others), it's an actual viable business model. They're pre-selling their merchandise, and like many businesses employing what's effectively a creative marketing tool. It's kind of a bit of a shell game - instead of the company spending a shitload of cash developing and bringing a product to market and then hoping they sell a ton at a high enough margin to turn a profit, they're trying to eliminate the guesswork by pre-booking orders. Let's face it, if they fork out the dough and the resulting product turns out to be a dud, it could kill them. Maybe that says something about the deteriorating business skills of startups today vs. years ago, but that's a different branch of discussion.
As for how it applies to Burning Man, first it's worth pointing out that you can opt out of seeing fundraiser posts on the board - see this post
for details. Second, Burning Man not only existed before Kickstarter, but burners were putting their hands out for money LONG before the term crowd-sourcing was coined. Hats were passed, tickets were raffled, parties were thrown, t-shirts and cups and other trinkets and merch were sold. I don't have any idea how many projects or what the percentages were, but I think it's more than most people think - before sites like Kickstarter popped up you'd only really find out about stuff that was happening in your local area. Back in my first year (2004) there were fundraisers for art (big and not-so-big), mutant vehicles, and camps. I'm pretty sure that it's more now, probably a lot more. Part of that may be that some people have become more radically reliant on others and see it as some kind of money tree. But part of it may be that more camps, art projects, and MV's are learning the skills needed to organize and execute on fundraisers (learning skills and being resourceful are good things).
Of course, what we think is a good fundraiser is often pretty subjective. We choose the projects to support that we as individuals deem worth our support. To me, Burning Man fundraisers (and most others, for that matter), tend to fall into one of two categories: the well-executed and the bottom feeders. Well executed stuff is easy to spot, they communicate a clear message, usually have most of the resources they need, and a pretty clear path to be able to deliver not only the project but the promised rewards on time (late delivery of rewards is the #1 complaint on those sites, as I understand it). The bottom feeders are usually easy to spot, too. Their use of language is often a dead giveaway. If their pitch seems confusing and unclear, or a poor set of goals/rewards (asking ppl to pay for what should be basic expenses, offering to sell VIP access), or if it's filled with terrible spelling/grammar, the campaign is largely a bottom-feeder. In the case of Burning Man stuff, it might be that they're radically self entitled people who feel that since other camps do it, they need to get in on some of the free money too. Or it could be that they had a great idea to do something (big or small), but just were in way over their heads and had no idea it was going to cost that much to do it and are now begging for help.
Treat kickstarter/indiegogo/wepay/whatever the way you would treat any other fundraiser - vote with your wallet. Cheer on the stuff you're excited about, and ignore the stuff you don't connect with. If you've reached your limit and are just plain tired of seeing them on the boards, at least you can turn it off
In the interests of full disclosure, I've helped organize fundraiser parties for camps I was part of in the past. One was post-event to help the camp recoup a few runaway costs and was a success, another was a pre-playa shindig to help offset the cost of fuel to haul our camp's big mutant vehicle. While that one did raise a few hundred bucks to help out, I think mostly it felt like a last hurrah 2 weeks before the burn. After that things seemed pretty focused on the work that needed to be done in the home stretch. My campmates and I are also considering the possibility of running some kind of fundraiser for this year. All our camp's expenses are covered by campmates via dues, and we also cover the costs of the art we're building, but despite being as cost-conscious and careful as we could finances are pretty tight. We're wrestling with it now and wouldn't do it unless it's something we could execute well, but I sort of hope we can pull it off without going that route. But I'd be lying if I said we weren't seriously thinking about it.