So, they make a dlc worth buying (the single player one) and they dont release it on pc. I feel backstabbed there, specially having bought bioshock 2 on pc.

Bioshock 1 was developed by irrational games, and published by take 2.
Bioshock 2 was developed by 2k and published by take 2.
Bioshock infinite is going to be developed by irrational games and published by 2k.

Now there is a conflict of interest regarding the decision to buy bioshock infinite or not.
Sadly, probably ill end buying the game because the game itself looks good.
And well, probably its not entirely 2k decision, probably the extremely long and costly games for windows live authentication / verification process has something with this news too.