Police originally encountered Oren at College Green Park and received a warning for yelling obscenities and disturbing the parade. Later, he went to the Iowa City Ped Mall, jumped on the stage, interrupted the scheduled performers, and went into an anti-Obama rant. He also got in trouble for "overzealous" dancing with various women. Oren was eventually arrested and charged with "interference with official acts" and "disorderly conduct/making loud and raucous noise".
Keep in mind, Oren didn't seem to have a problem with the Pride celebration itself. In fact, he was marching in the parade itself and seemed to support its goal. His problem was that he doesn't like the President's policies and got himself really worked up.
Both of Oren's charges are simple misdemeanors punishable by up to 30 days in jail and a maximum fine of $625.