CHICAGO, Aug 11 (Reuters) - U.S. Vice President Kamala Harris jumped into another divisive American issue ahead of the 2024 re-election campaign on Friday, vowing support for activists trying to end gun violence and accusing gun law opponents of "hypocrisy." Harris, who has embraced a more combative role as President Joe Biden's re-election campaign kicks into gear, took a swipe at Republicans who have blocked Democrats' proposed gun safety laws, saying such changes are no threat to Americans' constitutional gun rights. "There are some people who are just trying to sell a false choice ... that you're either in favor...