Again, that's your opinion and many people here will disagree with you. I actually found Bioshock 2 to be the weakest in the series (Minerva's Den aside) and I found the setting of B:I to be so refreshing in its departure from rapture (at least in the main game). Narratively, it was the strongest in the series easily for me.
So we see two completely different sides of the game here.
I am looking for gameplay, which I found to be mediocre, and you prefer more of a narrative experience which Bioshock Infinite does provide in both its setting and story.
Which is also why I would find Bioshock 2 to be the best in the series and you would find it to be the worst. The second entry focused on gameplay and put the story on the backburner, while Infinite completely downgraded the gameplay in almost every aspect.
I also think Bioshock 2 was the best. The narrative in every Bioshock game is garbage IMO, so at least B2 having good gameplay design actually redeemed the series name.
I would agree with this to be honest.