> it's not like the whole congress votes on how you're to be treated
Not the whole Congress, but how exactly do you think procedure and parameters for hearings are set and objections during hearings are resolved? Both the specific personalities in leadership positions and the attitudes of the majority matter a lot.
EDIT: It's true that there is a tradition of providing some semblance of balance in committee process, including hearings, with the majority (not necessarily by party) mainly controlling what items are considered and what hearings are held, and ultimately the outcome; but not only is partisanship greater than in the past, but precisely those traditions have noticeably weakened over the last couple decades and particularly in the current Congress.