Kirk: huh? not a damn thing for season 5 gets spoiled in 'Deconstruction'. what are you talking about? The Garibaldi scene? If so, that spoils nothing at all. I also don't get the concept of humans becoming Vorlons ridiculous. You have no problem with Vorlons evolving into beings of energy, but humans can't for some reason? And then you find the future dystopian stuff idiotic. Why? because it's not the usual Star Trek happy ending? If you honestly think humans will be these goody two shoes Star Trek loves to show a few hundred years from now, you're delirious. Seriously, do you pull random complaints out of a hat? I understand certain story ideas not being your cup of tea, but the things you call idiotic are just ludicrous.
Star Trek took it a bit too far (which even DS9 made fun of atleast once, with Jake trying to borrow money from Nog and it was basically bashing the concept of humans being "beyond" things like money) but B5 is much to bleak. I didn't expect Sheridan to make the future perfect. But, the Earth basically destorying itself is just stupid. It also makes no sense. What about Mars, or the other human colonies? Earth would not be left alone to revert to the dark ages.
Is it such a bad thing to think that humans may actually turn out atleast ok, and have a good future? There can be a balance between Star Trek's humans and a more realistic approach. B5 isn't it. B5 takes it about as bad as it will go. I personally don't like that route. In the end, it doesn't really matter. In my head, the episode is not in continuity. Much like how I ignore the TNG episode that hobbled the Enterprise's speed (presumably because the people in charge were taking stupid pills) or that a lone ship in the Delta Quadrant broke the Warp 10 barrier, I'll pretend that humans don't revert to the dark ages, and that the whole episode just doesn't exist.