They probably thought he was going to speak out against the surge. When he did`nt, they had to shut him up as quickly as possible. And Clark is just another Kos butt kisser.
Since they didn't let the Sergeant speak, we don't know if he was going to make a political statement, such as "support George Bush", a policy statement such as "the war is worth fighting" or a statement of the facts on the ground as he sees them such as "the surge is working", or "You assholes are hurting moral, badly" Those statements are all treated somewhat differently under the UCMJ .