Everything that this project can do, has been done before and is freely available. To clarify that: I've nothing against offering such a project for crowdfunding, but then they have to use a realistic price point.
Everything this project can do has been done and is available for free? Really? These other projects come assembled and ready to plug in and use? these other projects come with documentation and technical/customer support?
I haven't seen any freely available projects that assemble and test themselves, program themselves, and come with a phone number for support if something isn't going right all for free.
Looks like to me they want money for a finished product with support. Not everyone has the knowledge or desire to to take some project listing off the net and source the parts and build it themselves, most folks don't even own a soldering iron. Most folks want a finished product they can just buy and use and call someone for support if they have issues. Building your own project from parts on the cheap is fine for those that want to do so and have the knowledge and tools to do so, but that's a very very small minority of people.
Why on earth would you be pissed off about someone taking the idea to a finished product that non makers and non electronics people can just plug in and use and putting it up for sale and making a decent profit from it? As long as people are happy to pay the price where is the issue?
I would imagine most of the folks buying these are guitar players that just want the finished box to plug in and use and are excited to be able to easily download and add new sound effects in the future from the web and have absolutely zero interest in building one from parts at all and most likely also zero ability to build a project from parts.