It means that some courses are far less diluted (in demand even) than others. Again you're using one not very representative case as an example for every course, and its not suprising that things turned out the way they did seeing as sales isn't a particularly academic career choice and I can't imagine Mexican-American relations is particularly high regarded degree.
Don't you think that in your desperation to discredit higher education you might be clutching at straws a bit?
Don't you think that in your desperation to discredit higher education you might be clutching at straws a bit?