You're completely missing the point, then, because I'm not talking about balance. Let me approach it from this angle. How does it feel to lose to cloaked banshees early in the game because you don't have a robo or forge out and you lose your entire economy? Now how does it feel to lose a longer macro game? Obviously, losing always sucks, but a banshee destroying your mineral line that you can't attack also gives you this feeling of helplessness which I find much more demoralizing.
When I play Terran this feeling is pretty rare. I have a wall-off and anti-air at a very early point in the game. Not only are the possibilities of aggression against me reduced but people almost always leave my base alone aside from pokes to see what I'm doing until mid-late game. In comparison, 2 rax w/bunker, 2 port banshees, mass hellions, some sort of bio push, etc. is expected from Terran and ZvZ is mass ling, ling/bling aggression, or maybe a roach/ling push until the game stabilizes a bit. Protoss haven't been all that aggressive lately since they think they can out-macro you and beat you that way but of course cannon-rushes still happen and they used to be able to 2 pylon block your natural. The game may have been balanced overall (scouting decides whether most of these things succeed or fail) but the volatility of the early game made for some absolutely nasty losing streaks that the other races were much less likely to face and that's where (I think) a lot of the whining comes from.
Some does come from watching pros, of course, and we do have Idra to lead the way in whining but I think most comments like the one that started this discussion have its roots in personal experience.
