kickstarters are not preorders and are always something to be wary of, but in this case the platform is pc all the same. to someone who's already bought a copy you're just downloading it somewhere else.
I agree that backing a kickstarter isn't the same as buying something on a store. And again, it doesn't matter for me as I wasn't planning on getting Shenmue 3 on PC anyway, but they send out multiple emails which clearly stated "Steam" and not "PC" during and after the kickstarter was funded. There isn't much discussion that changing this is a shady thing to do. Even the poll to choose which version you wanted stated "Steam" and not "PC".
I understand that some people don't care as long as they can play the game and that is perfectly fine, but it was already known some people did care about that when they changed to EGS.
Is it the end of the world? No. Is it going to cost you goodwill for next kickstarter projects or any other game you will create on PC? I can almost guarantee it. I am not convinced this was a Ys.net decision as Deep Silver made that decission a couple of times before Shenmue, but it's going to keep coming up with their next games. I don't think a dev that had so much trouble getting their game funded needs this kind of negative press.
Also it's not because you don't care that other people's opinions on this aren't valid. They paid money for this all the same. Some people don't care as long as they can play the game, others feel like they paid for the Steam version (as this was mentioned plenty of times over the years on their kickstarter) and they probably wouldn't have pledged if it wasn't on Steam. It's obvious to me they feel betrayed, there is nothing wrong with that.
Ys.net/Deep Silver didn't do anything illegal, but it's close to it as they mentioned Steam before changing it after the kickstarter was funded and I don't think it's a good look. Shenmue 4, 5 and 6 will have a lot more trouble getting funded when they are going to be crowdfunded (no sane company will try to fund these money-losing games themselves any more).
The end result is that instead of the story not being complete with Shenmue 2 with no sequel in sight that the story will not be complete with Shenmue 3 and no sequel in sight. I don't think their next kickstarter will be as successful as this one was and they will have a lot more trouble finding a publisher for Shenmue 4 because of all this.
Hell, I think crowdfunding games in general is getting more difficult because of stuff like this (and that sucks for small indie devs).
People lose their trust in crowdfunding because of bad experiences (I for one will probably never crowdfund some electric product any more). Let alone if gaming news sites are full with articles about this.