"I wish your CEOs were here. They need to answer for this." "I'm disappointed that you're here and not your CEOs."
On one hand, I get that talking to the lackeys rather than the leaders feels like the corporations are not taking this seriously. On the other hand, I doubt that they would have obtained anything very intelligible from the man-children in power. I can't say for Jack Dorsey, but Larry Page and Zuck are not really known for being great conversationalists.
If the point is to humiliate the corporations and make them look like idiots in front of the media, then by all means Congress should have demanded to see the CEOs. But for any useful exchange, I'd say the lawyers were a better choice.