Look at is this way. If I warned you for trolling or abuse you might not be happy, particularly if I'd let another user get away with something similar. Other users might say you deserved it or I might have been having a bad day and you were the one who was grinding my gears.
But if I issued a warning every time you posted, you'd suspect there was a motive of some sort. If a series of mods issued you with a warning for trolling every post you'd made, then you'd definitely suspect that something was up. It would be very likely that, behind the scenes, we'd made a collective decision as a team that you were a deliberate troll and that we were going to clamp down on you at every opportunity.
The point being, when does a single bad decision (or series of them) become a definite, predetermined pattern?