He is "mainstream" in being known as a conspiracy crank. He claimed January 6th was a false flag:https://www.the-independent.com/news/world/americas/us-politics/joe-rogan-january-6-false-flag-b2385733.html

He just generally pushes right wing misinformation whenever he gets a chance: https://www.thedailybeast.com/joe-rogan-is-mainstreaming-right-wing-misinformation