It's a generational thing. A lot of the imagery of comics comes out of the pulps and the popular fiction magazines of the early part of the twentieth century. I always answer questions about why Superman and Batman where "underpants" by telling the asker to look at old photographs of Circus Acrobats. In this case, the earliest imagery of horizontal stripes on shirts I have seen is early twentieth century Paris where you have images of working-class toughs and "apaches" (thugs) who wore them with berets and scarves around their necks. New York (and the larger east coast cities -- I've mostly seen pictures of Boston, Providence, RI and Philidelphia because I have family connections in all three) did have a lot of people wearing horizontal stripes in the twenties and thirties (when my parents were growing up). I remember in the sixties being given a shirt like that and being told it was a "tough" thing to wear. These days, of course, we mainly are told that when you wear horizontal striped it makes you look fat, but comics tend to recycle imagery from the first half of the twentieth century, whether it is American Superheros or Manga or Bandes Desinees.