I'm so ****ing tired of people making excuses for this game. If Black and White can have a good story, then every game should.
Seriously, if your mindset is "it's all about the post game" then go play a freaking simulator. By that logic, Gamefreak shouldn't even bother making games at all, they should just make a breeding sim and an online component. Just because you're strangely satisfied by riding a bike back and forth doesn't mean it's excusable for a story as bad as XY's to exist in this day and age.
1. Take an actual issue with the story that has been pointed out many times in the past
2. Make that the villains' motivation
3. Completely avoid dealing with the issue by making the villains cackling Saturday cartoon villains that go out of their way to point out just how very evil they are every single time they get a chance
4. Throw in some power of friendship crap
That's Black/White in a nutshell. Frankly, they had the worst story in any of these games, because they had a serious premise but did the very worst they could with it. The whole uprooting animals and forcing them to fight each other thing has been something the games just ignored up until B/W, despite quite a bit of criticism of that aspect. And when the games do acknowledge it, it's in the most immature way possibly; instead of even responding to it beyond the obvious cop out "they get stronger if they partner with a trainer", Gamefreak just made everyone that agrees with it as blatantly evil for the sake of being evil as they could. They even made the villains go on about how they don't even believe in the cause, they just want to trick people to get power. The one exception would be N, who is a naive and annoying idiot who is eventually "won over" to the other side's stance on the issue.
Where the other games had mostly stupid premises and didn't bother replying to any real-world concerns because it wasn't needed, B/W had a very serious premise but squandered it completely.
By the way, the story doesn't have to be good if the gameplay is good. Unfortunately, most of the gameplay in these games is slow, luck-based grinding. Seriously, the cat has been out of the bag for a very long time now. They need to stop pretending that IVs are a mystery and get rid of the luck grind aspect.
Also, you got another thing wrong. The way you can tell that the fanbase is incredibly immature is the way they they treat everything with extreme arrogance. They think they're witty with their snide, useless comments and every other thread here is filled with complete idiots who just quote the same message over and over again without adding anything. If they have nothing to add, they have no reason to prance around just for the sake of being jerks.
The story part of the game is intended for children. The post-game competitive Wi-Fi stuff is intended for older players.
Because a story is "for children" means it doesn't have to be good? That's a horrible way of thinking.
Childhood is when someone is the most impressionable, what happens when we give them the story equivalent of "dangling keys in front of their faces?" As someone else noted above, Batman TAS, Gargoyles and Disney are great examples of the kinds of stories we should be showing the children that will grow up to be the future generation.
Honestly, Doug Walker could explain this better than I ever could.