The whole freemium model itself is not a problem at all, the problem is the developers that abuse it which appears to be most of them. You only need to look at Valve with Dota2 and also their popular hat simulator know as TF2 to see freemium done right. You never have to spend any cash in these games and it does not effect you experience at all.
What I hate is freemium games where they are pay to win or that you have to pay or wait hours/days before you can play again, this is where the problem starts and is driven by greed.