Because in the 1980s and early 1990s, when BSD was being developed at the CSRG, csh and tcsh were popular. If anything, it's retained as a nod to the history a

Because in the 1980s and early 1990s, when BSD was being developed at the CSRG, csh and tcsh were popular. If anything, it's retained as a nod to the history and heritage of the system.