Joe Rogan is addressing his use of a racial slur after a viral video showed clips of the controversial podcaster using it repeatedly in past episodes. Rogan, 54, took to Instagram early Saturday to apologize for “a lot of s–t from the old episodes of the podcast that I wish I hadn’t said, or had said differently. This is my take on the worst of it.” “I’m making this video to talk about the most regretful and shameful thing that I’ve ever had to talk about publicly,” Rogan said. While he now agrees “there is no context where a white person is ever allowed to say that word” and said he hasn’t d…