As stated before, the difficulty is in deciphering the subjective bits. Stealth could see K. Rool as a prospective winner, therefore ruling him out of this tweet, or see other characters with a louder hype factor, such as Shovel Knight or Banjo, in that role, keeping him viable as the mystery character.
And the "eventual addition" thing qualifies as well. I, for one, see K. Rool as an eventual addition in terms of, the split second he gets into a new game, he's pretty much in Smash, thanks to everything else he has going for him. But outsiders with less knowledge of Retro say that "K. Rool shows no sign of being in a new game so he has no chance beyond this ballot."
For what it's worth, I've heard conflicting reports on Stealth...some say he's a GameFAQs troll who hates K. Rool and would therefore not be "excited" for him, but he has a tweet saying K. Rool was one of the characters he voted for.
If not just for the character himself, I want K. Rool to come first so I don't have to speculate such murky **** anymore, heh.