I hate to say I feel a little conflicted by this. While it's basically a dick move, it's entirely within Nvidia's rights to control their own marketing. As a gamer/consumer, I really don't care if I see a review a few days before or after new cards come out. Considering how hard it is to ever get new graphics cards, it's not like early reviews even matter fur 99% of consumers. I get that if you're a youtuber who relies on beating others to the punch with video uploads for your income then it's a pretty lame situation to be in but it's not Nvidia's job to make life easy for youtubers. If the hardware unboxed guy was a marketing rep for Nvidia and he wasn't pushing the new features of their product, they would surely fire him. I don't see why providing early samples would be any different. Nothing is stopping anyone buying the graphics card themselves.
It seems fairly obvious that early reviews for any product will be skewed and the real lesson here is that early review are a bad practice in the industry overall.
No argument that it's lame for Nvidia to do this but it doesn't really bother me either. The way I see if, people who get early samples are basically entering into a transaction with Nvidia that has an understood mutual benifit. If that relationship doesn't properly benifit one party, they have no reason to maintain the relationship. Providing them with something of value that they can use to make money is not all that different from sending them a check directly to me, so I just look at it as if Nvidia fired a marketing rep.
A lot of youtubers do this, make a huge deal about something that really only impact them and try to get their audience to care about it as if they have all been greatly injured, but it's just not reality in this case. Nvidia could stop sending early samples to anyone and in wouldn't change a damn thing for anyone except the people who did early reviews. There are times where companies need to be kept in check with public attention, but this isn't it.