Because you didn't made and repeated the experiments to prove it?
I played many freemium games and legimately exploit everything in them to the fullest effect. In most of those as a f2p player I'm as competitive as most heavy spenders because I know more about that game than they were, that I can put up an even fight despite heavy deficit. In a few of those I went so far that I understand the game more then the developers. Hell, I even called the developers stupid when they released something incredibly broken in the updates.
Don't underestimate the complexity of this game, if a layman can do it they won't be earning millions from this darn thing.