But it is. Here's how things typically go: person in front of the Congress has a certain political affiliation, perceived or official. So one party (their own) runs down the clock asking them ultra-softball questions they can easily answer truthfully, while the other side asks difficult question which, if they answered them truthfully, would doom their appointment or invite further legal scrutiny, so they lie instead. On some occasions (Clapper or Clintons to mind) they just blatantly and unceremoniously lie to both parties, with impunity. On other occasions (Zuck, Pichai, others) they lie by omission or promise answers later, even when it's quite obvious they know them at the time. Nobody in the press ever checks what answers they provided "later", or whether they have provided them at all, or whether those answers were "truthful" or not.
And yes, everyone in Congress is quite into inside trading too (often holding large positions in companies they "scrutinize"). Multimillion dollar fortunes can't be built on $174K/yr otherwise.
This is a caricature of open hearings scripted for popular consumption. They're coördinated campaign events where, in essence, both parties agree to suspend legislation to win points with the uneducated.
With respect to "political affiliation" and related biases, you're ignoring the significant areas of bipartisan agreement with respect to potential (note: not proposed) legislation. (Our political culture goes to shit when legislation is actually proposed.)
And yes, everyone in Congress is quite into inside trading too (often holding large positions in companies they "scrutinize"). Multimillion dollar fortunes can't be built on $174K/yr otherwise.