Noone is mad that they're producing a mobile game. It's the way they presented it that was disappointing, and the way they handled feedback that makes people angry.

Can you imagine being at a Apple/Node/Linux/Microsoft conference and actually booing at one of their product announcements? What would it take for you to actually boo as opposed to just standing up and leaving that presentation, or simply start fiddling with your mobile/laptop and ignore the presentation?

I presented the same case to a friend of mine who has been driving a truck for 20 years, who each year pays to attend an international transport conference. He saw the severity of the situation instantly.

If you're unable to imagine yourself _ever_ booing literally at such a scenario, then remember that it was a minority of the audience at Blizzcon that booed. Probably not more than a handful of people. Out of hundreds, if not a thousand attendees.