http://Michael and Mike, one of you knows me and knows I'm probably somewhere in between on the proper attire spectrum. I have no problem with a private club being on the strict side. Myownself, I can't stand the 'grungy look' or whatever the slacker set call it. But, at a public facility, it seems to me not to be a good idea for us older folk to start acting like the grungy set in the wardrobe dept., are persona non-grata. I don't care for a strict club policy that is so stiff that cargo shorts are verboten. Yet, wifebeaters or even collarless tees are understandably in my mind OK to regulate and forbid. But, I think it has to be allowed at a public facility, if the welcome mat is to be out to invite new blood to the game. As stated above, it is a fine line.
Obviously, the real issue ought to be the behavior of the folks pushing the dress code. If they act as grungy as they look and show no respect or consideration to fellow golfers in etiquette and care of the golf course, then boot 'em. But, I think it is safe to say, I've seen bigger a-holes giving golf a bad name and image in the arrogant behavior dept., whilst sporting expensive and stylish golf attire, than the hat on backwards crowd.
But with diverse sensitivities and attitudes about what is etiquette, appropriate attire, and the conventional vs unconventional or nontraditional, quite a lot is left for an offended party to step back from participating in the game. It is that negative cause that is best to avoid by all that would like to see the game grow or maintain. I think the scale isn't a fixed measure based on one set of standards.