He'd expected he would need to let someone else chair the committee — better if it's him, of course, but not worth sacrificing so much political capital for that he can't accomplish any of his actual goals. He's happy to go along with approximately anything that won't interfere with his own project, as long as the person proposing it is willing to do the same for him, but it's better not to say that sort of thing outright, it makes you look weak and desperate and gives people ideas about the sort of thing they can demand of you. Only one sortitioned delegate, which is fortunate insofar as barely-literate peasants have all kinds of confusions that might need to be straightened out before this committee can address its actual business, but unfortunate insofar as most of them can just be bribed. A straight majority of the room looks to be some sort of marginal nobility; he hopes their interests will straightforwardly align, such that no one sees a need to contest his suggestions, but it's not something he can count on.
In the end, no one else seems interested in putting their name forward, and he was the one who proposed it, so he ends up in charge practically by default. It's always nice when things work out like that.