Although people go over the top in rudeness, which doesn't help anyone, it's a fact that a lot of bug reports by customers to big companies get ignored. So the screaming is not entirely unwarranted.
And there's always strength in numbers, if 2000 people complain about something (ignoring the language), it tends to get noticed more than if 1 person would report it and the rest thinks "hey, it's already reported, let's shut up and wait".