I don't think the problem is I paid for it and now it is free. That is not a big deal to me (but a small thank you something would be nice).

The bigger issue is that they degraded the game because of the free players and subjected those who paid to the same ads and noise that you wouldn't expect from a free game.

For example I paid for TF2 and don't really care that it is free now. They do give me an occasional crate to tempt me to buy a key but it is fairly unobtrusive (and I think they had that before it went free anyways). If I was asked to buy stuff after every game I would be quite upset and would like my money back.