See bribroder link to the reddit page for an idea of how far what they claimed they sold was to what they were actually selling, and it will help you see that as a cautious gamer, if you actually went out of your way to specifically check for features shown on official release video and/or answered as yes/no question by the game's lead, you would still be fooled. The reddit comment matches direct interview answers with major missing features.
When you see two factions doing some major warring in space, and the guy present it as actual gameplay that's in the game's build and says "Like here, we're at the battle between two warring factions. I could join in, I could take sides." and then there is no fleet battles anywhere in the game, I have a hard time blaming the players for their expectations.
I strongly disagree with the crazyness displayed by a lot of people, and those that go as far as death threat should be refered to the police. But this is not a case of "rabbid fan attack dev who couldn't reach what marketing promised", he put his hand in the fire to grab dollars, he got the money and he also got burnt.
It was so bad, for a while valve made a exception to its refund policy specifically for no man's sky, so that players could refund it even after dozens of hours, because the dev was hiding behind the "you have not played enough, you will unlock it later in the game" trick.