That particular implementation (NetBSD's) (which is transcribed in to the article) does something more optimized than making repeated calls to `putchar()`. But

That particular implementation (NetBSD's) (which is transcribed in to the article) does something more optimized than making repeated calls to `putchar()`. But as pdw's link shows, what you suggest is exactly what the historical implementation was. So NetBSD is simply matching historical Unix.