Because we are all individuals and we can do what we want.

Some of us like to watch things to get pumped up.

to wet the appetite, get the juices flowing so on and so forth

What he said.

And it's not like they're showing EVERYTHING. Just bits here and there to keep the hype up. Everyone has TWO fatalities/Heroic Brutalities (man I still cannot deal with the ridiculousness of that name) .. and aside from Joker, we've only seen ONE for the other characters so far. So there's still a lot that we haven't seen.

As much as we've seen, there's twice as much that we still haven't. (For instance, we have yet to see barely ANY Kano, Jax, and Baraka gameplay)

I doubt anybody here feels like they've spoiled the game for themselves.

You have a choice. Either watch, or don't. No one is forcing you, some of the people who aren't buying it still want to watch just for suspicion purposes.

nothing's really been spoiled. We don't know the ending or most of the events that lead to it and we don't know if or when MK and DC will team up.

Well if you take the amount of the game spoiled here and compare it to Armageddon you'll see it very differently. Although I'm avoiding too many story spoilers the only thing I would not watch would be the intro. I'll watch it in game

I think the MK team have showed us pretty much every thing. I doubt there's any "goodies" left to be found. After all, Midway never give them any good amount of time to produce a quality game.

That's funny because this game looks to be the first quality MK game in almost a decade. Throw escapes, Wake ups, Free-form fighting system and tournament calibur fighting game players testing the gameplay (as confirmed here http://www.trmk.org/games/mortal_kombat_vs_dc_universe/prima_guide_author_interview/)

exactly