Clark Kent…
A soldier is a soldier when he is in uniform and when he is not in uniform. A soldier behaves like a soldier when he is in uniform and when he is not in uniform.
Although I don’t disagree that a frum person should dress in a fine way and in a way that identifies what he is, and I am not against wearing a black hat, I am more interested that he can be identified as a frum Jew by the way he ACTS (in business, to people he encounters on the street or in a store or on a train or bus or plane) than by what is sitting on his head.
AND… most importantly – that the way he acts should not be a stira to what the black hat SHOULD imply.