Yes, marketing made a big mistake: they made believe that everything was going well while the game is one of the most buggy I've seen. It's early access, but according to their marketing, it should have been much more stable. After all, aren't the developers supposed to play it all the time because it's so much better than KSP1? Given the gap between their marketing and the games delivered yesterday, it's not surprising that they find themselves so poorly rated on steam.
I also think that the developers have nothing to do with it. They probably used the latest dev version without a debugging session because the release date was decided and their bosses didn't want to postpone it anymore.
I am one, to my great regret, of those who asked for a refund. Given all the current bugs and all the features they want to add, I don't see how they're going to get out of it. I would wait 6 months to a year to see how it evolves. I hope it will finally be good enough to buy it and enjoy playing it.