For me, I've long had the impression that "Br0s and D00Ds" is who the game was marketed at, based on the ease of access and the flash. Not necessarily the people who played D2 as teenagers and are now adults.
The lack of professionalism (in an admittedly private space) just kind of reinforces that opinion from me. That response is just a reflection of how shallow and honestly shitty I feel like D3 has turned out to be. It's like, if you don't like D3 you're "a loser" because all the cool kids know Blizzard is like, wtf awesome, bro.
It is because D3 earns money by people using its market.
"The people who played D2 as teenagers and are now adults" is not the market for D3... it is "Bros and DOODS" the kind of people who would pay a lot of real money for digital things that will be outdated as soon as an expansion hits.
A lot about understanding a game is about understanding the Audiance. It is why I stopped picking on Koei for making the exact same games over and over again with slight alterations or steps backwards, their audiance doesn't WANT a new experience.
In the same way D3 isn't failing. It simply isn't for you because you are not the kind of person who will spend 500 hours on it and spend 50 dollars on items.
Mind you I am pretty disconnected emotionally from D3 mostly because it is an abomination of storytelling especially to those who were invested in the story from the start. With fists so heavy it was like they strapped pigs to them and plot twists so groan inducing that it was like they got it from Fanfiction. Gameplay wise it has boiled down its gameplay so much that something is lost, the ownership of your characters is sort of gone.
So that is why I am not really enraged. The game has sucked out any rage I had and left emptyness with another side of me just laughing at how this all turned out.
Heck D3 probably wins the "Worst videogame story, of games where the story matters, of the year". I mean yeah Mass Effect 3 has a terrible ending (and even then I don't think it is as bad as people say it is) but it wasn't a train wreck from start to finish like D3 was.