People often equate "Public" with meaning "middle-center" or "apolitical". Many would claim National Public Radio (NPR) is middle-center, politically-speaking.

Plenty of people disagree with that statement, and those who agree tend to like NPR's messaging - hence the "bubble" you referred to. Good, non-partisan reporting should make "both sides" groan from time to time.

If you find yourself in agreement with nearly everything said, then it's a fair sign the politics lean "your direction".