A Lowell attorney and amateur golfer is aiming to evade insider trading-related criminal charges by arguing federal prosecutors have unfairly targeted him while sparing his golfing buddies who made similar trades on American Superconductor Corp. stock. Douglas Parigian contends the government is engaging in "selective prosecution" by charging him and Eric McPhail , a fellow golfer from Waltham, for allegedly trading on nonpublic information about Devens-based AMSC to rake in hundreds of thousands of dollars, but not the other members of their six-man golfing group.