A national rock-music and pop-culture critic came to Iowa this week, with the message that freedom may include stuff you don’t like. Tim Riley says living in a free society means reading and hearing things you sometimes don’t agree with.He says it’s one reason we’re at odds with other cultures, because we’ve flourished with free debate and open-minded exchange, on politics and other things. Riley says it calls for careful choices when our rights conflict with each other.We make exceptions like not yelling “fire ” in a crowded theatre because it’d cause a danger so while defending absolute freedom you make exceptions. Riley says the danger lies in making an exception to free speech whenever the speech is some kind we don’t like. He says there are values that aren’t subjective; ideas like being able to openly disagree are part of being an American. Riley says the rush to pass security rules in the wake of September’s terrorist attacks has hurt all American free speech.He says it’s not erosion, but with new technology and terrorism threats, the lawmaking is too broad. Riley contributes to the Washington Post and National Public Radio. He spoke this week at Drake University.