It's because of unfinished games, "DLC" that is published by pieces of crap known as EA, Ubisoft, and Activision.

Because this is war, son.

Ideals are peaceful. History is violent...and full of fanboys.

To be completely honest, I feel like devs are intentionally being more critical because they know its the very start of a generation and the games will be better later on.
I mean, what do you do when a clearly superior midgen game has the same score as a launch game (10)?
Also possible, reviewers aren't getting paid because the companies know launch games will sell anyway.

Because there are fanboys and the initial portrait of gaming has been tainted. Of course, some of this is opinionated as well.

The internet gaming community is the minority (gamers who talk about gaming outside of just gaming) who reacts loudest to a smaller minority (review sites) based on their preference. Using games like WD, Destiny, and TF as examples, the internet would have you believe they are awful. The average gamer though would say they are great games.

Internet community goes online and looks up interviews. Average gamer looks at the ad on TV. Internet gamer has above-normal expectations because the PR guy hyped the game on hotgamingnewssite.whatever. Average gamer thinks "that looks good" when they see the ad on TV. Above-normal expectations not met, and for whatever reason, the game is a 0 user review on metacritic.

A large number of people, specifically in the user reviews area of a scoring site, only use two scores: 10 or 0. To the internet gaming community it seems like games are either "the next big thing" or "not worth playing at all".

Because nerds are obsessive, and in many cases often even bitter types of people? lol

Because the best games today are frequently made by indies and that rubs home that there's something wrong with the big companies and the trash they so often release.

The fact that many of your favourite genres and sub genres are barely touched these days, yet we're inundated with so many uninspired linear fpsers and boring open world games.

The fact that although the likes of Bioshock infinite, gta v, tomb raider etc are great we know we won't care about them 10 years from now.

The fact we know 10 years from now, Quake 1 will still be the best single player fps ever made (With duke nukem 3d a close second), and Mario 64 will still be the best 3d Mario game ever made, despite the fact that there are so many ways both those games could be improved upon.

The fact we spend far to much of our lives running from waypoint to waypoint in dumb pretentious games that don't let you do anything for at least the first 30 minutes and when they do finally let you do something it feels like exactly the same stuff you've done countless times before in so may other games.

The fact you realise many high profile games of the past you hastily dismissed 10-20 years ago are actually much better and much fresher than the bulk of what you play today.

haters are gonna hate...

You hit the nail on the head.  

This seems to have been compounded by the fact that we now have more "adults" than ever who were born AFTER the internet went public.  Some of us remember the days before the internet.  Some people here don't.  And I think that makes a difference in how you act, and how you set your expectations.  The instant gratification and the social media and the tweets and the likes and all that other bullshit has done very little but turn internet users into a bunch of spoiled brats.  I can see a huge difference today than even 3-4 years ago.  Things have gotten considerably worse.

Just imagine what it will be like in another 3-4 years.