I never asked the station to defend the position. All I wanted to do was let them know that the commercial was unconvincing. Should I have contacted the union rather than the station? Probably, but contacting the station was more convenient for me. At any rate, if I had been the station person who took the call, I would have thanked the caller and then I (as the station person) would have contacted the union person who bought the ad and given them the feedback.
Please read my original post. Nowhere am I questioning either the right of the union to say what it said, or the right of the station to air the ad and make money. All I was saying was that their arguments carried no weight. My point in the post was that by voicing this opinion, I was accused of being anti-first amendment.