A Senator is the CEO of a decent-sized public policy research and advocacy organization. He steers the ship, appoints senior staff, and handles the most important negotiations and appearances personally. He doesn't get in the weeds on background research. His
office is in constant debate, negotiation, and consultation with a complex web of think tanks, advocacy groups, pollsters, campaign operatives, the White House, and other Congresscritters to develop policy and negotiate its passage. There's an entire professional ecosystem of policy wonks and career staffers dedicated to this sort of thing. (Only some of them are corporate shills).
If Senator Graham genuinely wanted to know about Facebook's competition, there would be legions of staffers and thousands of pages of reports on it. If Senator Graham were genuinely not sure what to do about Facebook, there are exceptionally well-informed people in his office to summarize the landscape, the propsals, the pros and cons, and to debate the finer points, who are deeply familiar with everything AEI/Heritage/Cato/Brookings have to say about it, etc. because that's their full-time job.
By the time you hear a pointed question in the committee hearing room or a speech in a floor "debate" from a Senator, they've been over it with staff, decided on a position, and calculated the optimal move to present to the cameras. That you enjoy or agree with the thrust of this particular show has no bearing on the theatricality of committee hearings as a tactic. They wouldn't do it if no one enjoyed it.
It's not that politicians don't debate things in good faith. It's that they do it with and through staff (who are more like the people you find in high school debate than televised election debate), behind closed doors, and not on the floor.