Wal-Mart appears to be retaliating against groups that have organized historic protests against its labor practices. The retailer filed a lawsuit against the United Food and Commercial Workers union and its affiliated group, OUR Walmart, in a Florida court. The suit accuses the groups of trespassing on Wal-Mart property 73 times in 13 states over the past year. Wal-Mart workers are not unionized, but the UFCW has demonstrated in support of employees’ calls for better pay, benefits and working conditions.