After Sentinel Prime being revived he demanded the Pillars to be returned to him, but Mearing told him that they will be returned if humans say so, after a couple of arguments with the Autobot, Sentinel went for a drive with Optimus. Now the question if it wasn't for Sentinel you think Optimus would demand the Pillars to be returned to them or he would leave were they are in the Military base?
He would leave them in the base. Since Sentinel himself appeared to fear the idea of the Decepticons getting a hold of them, Optimus likely supported keeping the Pillars in a top security vault. Plus, Optimus knows not to bother arguing with the bitch Mearing was; "diplomacy" wins out.
Yeah, Optimus works with humans the best he can. If they won't give up the pillars, he's not going to start fighting them to try and get them.
Mearing was so damn condescending and ignorant. I honestly wish Sentinel had taken her out when he trashed the base.
There's also the fact that they had no use for the pillars. It wouldn't have helped the Autobots at all. The fact that Sentinel was so insistant on getting them back was the first hint that something was up.