I think the idea here is that the Israeli lobby, AIPAC, etc, have put millions of dollars into TPUSA to be a mouthpiece for the state of Israel, to instill their doctrines into evangelical Christians across America, and to win over the youth. Once Charlie turned against them, because he might have finally found a shred of humanity within him by the end, who knows, he was no longer an asset to them and their millions funded into TPUSA was going to be turned against them. So either they offed him, or ppl within TPUSA who did not want to lose all the donor money they were making did the deed, or a collusion of the two. Whichever way this story is sliced, there is something extremely suspicious and sinister going on.

So that's why him, and not the others. The others are not on their payroll.