I think Lebron and Wade's statements came out of their legit fear of the Nets this year and their frustration that KG and Pierce did not fade into the night and are an even more legit threat to them this year than ever.
This is clearly what is at the heart of the matter. LeBron and Wade know all too well the warrior mentality of KG and Pierce, and likely are none too pleased they again have to deal with them, this time on a loaded Nets team.
Garnett, Pierce, Williams, Lopez and Johnson is an absurd amount of talent. Throw in Kirilenko, Blatche, Evans and Terry, and you have one of the most loaded rosters I've ever seen assembled.
You'd have to be clearly delusional to think the manner in which KG/Pierce were sent to Brooklyn is in any way similar to the manner in which Allen left for Miami. One player left of his own free will, as a free agent, while the other two were forced, by trade. KG's no-trade clause only matters in that he could have told the C's "screw you, you don't want we anymore, then you get nothing". Based on Ainge's actions this off-season, it was clear he had no intention of allowing KG or Pierce to play for the C's this season.
But I love all of this. It is clear the rivalry between the C's and Heat has now transferred to Brooklyn. Just look at last night's preseason tilt between the two teams. That foul by Pierce on James was clearly made with the intention of letting James know Miami is going to have to reckon with the Nets. KG and Pierce clearly intend on bringing the same ferocity and swag to Brooklyn they had here in Boston.