Longtime People magazine critic Leah Rozen points out that Joaquin Phoenix is basically doing an Andy Kaufman shtick in “I’m Still Here,” a purported documentary (that everyone thinks is a mockumentary) in which Phoenix pukes, punches an assistant, does drugs (or appears to), calls hookers and generally behaves like a lower-body aperture for 108 unbelievably repetitive minutes. Is Phoenix simply doing an intentionally obnoxious character, the new Tony Clifton? I think so. Here’s something else Phoenix has in common with Kaufman: Everyone who endured Kaufman’s Letterman appearances, his “Mighty Mouse” act, his wrestling adventures, and his lounge-lizardy Tony Clifton as they happened can attest: Kaufman wasn’t actually funny. He was doing performance art, not comedy, a piece aimed at an aggressively hip audience. Some people will suffer through a grueling display of untalent if they can be reassured that it’s “edgy.” Leah Rozen, Jeffrey Lyons and I all loathed “I’m Still Here” but my hip colleague Sara Stewart liked it, and so did lots of others, according to Rotten Tomatoes. The film has buzz, or anti-buzz, or something.