Candy Crush, Farm Ville, most prominent examples of F2P are nothing short of gambling. Zynga (and I presume King as well) has large teams of psychologist focusing solely on making the game as addictive as possible and exploiting that addiction, i.e. making addicts pay.
What are you talking about? There is no chance involved in most of the F2P games, without which there is no gambling. That's what the word means!
Candy Crush is ostensibly skill based, being a bejeweled-match-3 type game and Farmville and the like are based around time, not chance. (You get X actions per day, and can spend money to get more actions)
