Calling PC gamers self entitled and angry clearly shows you do not understand the problem. This is bigger than the announcement or absence of particular games.
Blizzard developing Diablo Immortal at all leads to the idea that Blizzard are now in the business of chasing the mobile money in China and less so towards their real bread and butter which is PC gaming.
Mobile gaming doesn’t take much to develop and can lead to massive returns; that’s why they would be doing this. Instead of giving the players what they want, they appear to be giving what the investors want. The pursuit of greedy profits likely means they have their priorities elsewhere.
Shoving a mobile game to a PC gaming crowd and the lack of a Diablo for PC announcement leads to the accusation that Blizzard are out of touch with their core audience. They thought Diablo Immortal would satisfy the crowd but were shocked at the reaction because they did not expect it. If they are unable to read the room or know what makes their fans tick, what hope do they have in delivering a quality product?
These are just symptomatic of the overall problems with Blizzard and Activision Blizzard in general. There’s a lot more to this than you probably know or give credit for.