Thanks for your thoughtful response, Audra. I should have explicitly said I'm pro-union, too. I've walked picket lines with union members (e.g., Justice for Janitors, teachers on strike, etc.) and I don't cross the lines when a union is on strike.
I also firmly believe that collective bargaining has yielded enormous gains for all workers. Yet I think this particular union lawyer was a real asshole. He may have been acting well within the law (as he never committed any unlawful act that I know of) but I found him unethical and slimy.