People complain because game companies, developers, and publishers promise that their game is going to be the next best thing and the most mind-blowing gaming experience ever.
And they fail to deliver.
If someone promises to cook you a nice breakfast in bed and they bring you a packet of crisps you might just feel like they've not been totally straight with you.
Now repeat the same scenario, but this time they have to cook multiple servings of the
same breakfast dish to tens of thousands of people. Tens of thousands of people with different preferences, from extreme vegan to "hates anything green on their plate".
You can feed them the finest dish you want but there will be a proportion of the metaphorical breakfast recipients that whine because "it's too salty" or "not salty enough" (examples chosen with great care

), because it completely doesn't suit their diet, or just don't like it so much they equate it to a packet of crisps.
The forums here are several hundred people all expecting their breakfast to be delivered to them in bed for the next 10 years, but we all have the same game - or dish - and
somehow everyone expects their dish to be handed to them every day as if it were a bespoke meal suiting their every preference.
So the solution is to obviously sit on the forum complaining about this dish not suiting you until poor FD in maid's uniforms (brief mental diversion there) start bringing you your dish - but be happy to ignore the fact that several hundred vegetable-phobes are now being given steamed cabbage for breakfast.
And of course much like this analogy, the majority of forum suggestions are on the same level as someone insisting their breakfast be boiled cabbage for 10 years.