Threads like these really show who actually plays or pays attention when they are playing Zelda games.
No, they are not the same.
-The levels change, they simply share a name and theme.
-The items do stay very similar... kinda like how every fantasy game has swords and bows, and every (non futuristic) FPS has guns, and slightly different guns...
-The setting, like the levels both changes yet stays the same. Its set in a specific world, they can't change it entirely, but there are differences from game to game (even moreso when you take Majoras Mask, WindWaker, Phantom Hourglass and Spirit Tracks into account)
-The plot is not the same. No... No it isn't, you can say it is as much as you want, that doesn't make it true. Again the games mentioned above are considerably different from other entries (and indeed each other). Even excluding those oddities, the simple act of featuring Ganon as an enemy does not make the story the same.
The only thing that's really stayed the same is the core gameplay:
Go to temple, find item, use item, beat boss, get to next temple, etc.
But wait!
If it didn't share gameplay, what the hell would make it a Zelda game?
You mightas well have a go at Mario/Monkey Island/CoD/Diablo because the core gameplay hasn't changed that much (ironically the transition from 2D to 3D Mario is probably the biggest leap) if at all.
If you don't like the games just say so, but stop trying to blame the game, or make it seem like you're the only beacon of intelligence in a sea of fools. We like the games because we find them enjoyable, we see the differences (however subtle you consider them) because we pay attention, you don't because you don't want to.