When a product is pushed as essentially a silver-bullet -- often by people who have never and will never actually build anything with it -- it is naturally going to get a lot of backlash by people who see through the problems, and moreso by those who buy the hype and then smash into the reality halfway through their projects.

I speak from personal experience on the first point, while the second has come from countless real-world case studies. A couple of years back I had several widely distributed pieces declared "trolls" because I essentially called for a sobering reset on the NoSQL hype train. Every single thing I said has been well proven out since, so there's that.