Still you misunderstand what Computer Science is, and have misplaced expectations. Computer Science is already defined. And it is not learning Linux, Windows or *nix. You want to define it to be a field that focuses on knowing something like Linux. Linux is like a pencil. A tool(amongst many). An environment, a case to study. Knowing Linux brings no validity to a Computer Scientist. It merely adds value, but isnt the crux of the field. A Computer Science degree from whichever university would be perfectly valid without having to learn Linux BUT lacking if it does not teach OPERATING SYSTEMS CONCEPTS. One can be a Linux guru and yet totally clueless about the (computing) fundamentals that make it such an elegant platform.
Good of you to mention renowned universities. You might want to have a look at the courses of those universities. You mentioned MIT. Also have a look at Stanford. You may also like to know that the courses offered by Zim universities you seem to look down on are based on globally agreed curricular that those same "renowned" universities that you revere also subscribe to/share with them. Resource availability though is their weakness.
Using Pastel doesnt make you an accountant. But a totally complete accountant can exist without having to know Pastel.