I suppose I am prejudiced against them because my father warned me against them from a very young age. The reason he gave was practical: once you have an indelible mark like that on you, you are instantly recognizable and traceable, even if you are fairly anonymous in other respects.
Now he was as honest as the day is long, and unlikely ever to be "on the run" from the law. I wonder if what he had in mind was the possible rise of some totalitarian government. He lived in London before and during WW2, and saw the Moseley Fascist marches, and had a pretty good idea of the dangers of Fascism.
And while we are not Jewish, he was possibly also thinking of the tattoos on the arms of concentration camp victims.