ah, yes, "if the players dont like it they can simply stop playing and not say anything at all". how i love this argument. you see, this argument is literally pointless, it's worthless pandering to people with sensitive feelings. you literally answered your own question in the first two sentences; why does the dev get hate? well, isn't it obvious? you listed a lot of the minor issues people are having with the game, let alone the major ones that have been mentioned on here.
tell me; how is a video game dev supposed to know what players are finding wrong with their game? how will they improve if they dont have anyone to tell them what's wrong in the first place? sure, they're a dev, but they can't do everything, and sometimes only some players will encounter a bug while others won't. it goes like that, really. players want their voices to be heard, and want devs of games they see with potential to improve. sure, they could be nicer about it - but the tone-deaf "i dont know why players are saying the game sucks" after pointing out many reasons why the game sucks is just *chef's kiss*.
look; you don't want a dev getting hate. that's ok. but when the game is slated for a full, fully-priced release that people will have to pay money for - on other platforms at least - and there are game-breaking issues that dont seem to be getting solved? then yeah, players are gonna be pissed and angry because it doesn't feel like they're being listened to and, therefore, like the dev doesn't really care.
also, people are scared of another Breeders of The Nephylem dilemma - the dev casually ignored players and their desires, actively does whatever they want, burn themselves out with 'no ideas', and then complain when they get backlash after not updating the game for literally over a year now. and they, too, were planning to seel it for a full release.
THAT'S why players are being harsh and complaining.
Or maybe people should check back this thread after a few years to see if it's a playable stage then.
