People's time is worth nothing and money is the only thing which matters and people who value their time more than some small amount of money don't deserve to be able to enjoy any games?

>If the mechanic exists solely for gameplay reasons, rather than for manipulating the player, it's not taking advantage of anyone.

If a person spends 100 hours in a game which requires ridiculous grind that's less evil than if they spend 5 hours in a game and spend $2 to unlock extra turns sooner than just waiting while having equal amounts of enjoyment?

Time is money. You may not value your own time but I and others do. Even in "pure" experiences if elements of play are there for gameplay reasons (every game having different goals) it can cost a person a lot of money just by playing it for a long time.