Wait, what? I think KP went to the CPL after the meeting with Strauss because he was told, in no uncertain terms, that it didn't matter how many hundreds he scored or how overwhelming the public pressure was. As soon as Strauss was appointed, there was no avenue back for KP.
A few more hundreds doesn't get Strauss sacked and Piers Morgan hired as England's Director of Cricket. Public pressure doesn't un-send text messages. 100 more runs wasn't going to do anything to get him back in the team.
Whether that decision by the ECB/Strauss was right or wrong is another debate entirely (a very tired one, in fact); but when KP has been told that there is literally nothing he can do to change their minds, its hard to blame him for going elsewhere. If anything, it's probably better for everyone that he decided to move on.
The tweets are him desperately trying to stay relevant; I think he knows that he's not getting a recall, and just wants to stir **** and get the attention. Because he's, y'know, a pretty dire bloke like that.