Maybe the Senate’s deference in part is motivated by their belief he may run and win in a few years and they hope to win favor from a man they may end up working for.
Secondly perhaps it is motivated by them not wanting to appear too knowledgeable nor too much of a threat to Mark, to put him at ease, lest they otherwise provoke his wrath.
Third I think their attitude is certainly motivated by the awareness, from those in governments, just how powerful internet giants, particularly FB, are. I believe in no small ways have these companies upended the conventional relationships of individuals, and corporate individuals, to the state. They command vast resources, such as people and intelligence ( and automated processes pertaining to them, i.e, algorithms or bureaucracy, pick your favorite term ), traditionally the purview only of state entities.
I’m quite sure that many in government consider these companies are direct threats to the future of their model of governance. But they also feel they must handle them very delicately. Because they do not want to risk a premature confrontation they are unprepared for.
But if any person alive today was going to mount some sort of the future coup against conventional government, spearheaded by the new tech elite, then Mark is a perfect candidate. He is a student of history and demonstratedly strategically effective.
In this light, perhaps the biggest takeaway of a public questioning such as this is how much of a theatrical side show and possibly a distraction it is from the new reality these powerful groups find themselves contesting.