Linux is popular mainly because leftists don't want to see Microsoft's Windows computer operating system remain the dominant operating system in the world. Large numbers of unpaid programmers write code and contribute it to this operating system, which is then made available for free. They seem to do this for no other reason than to stop Bill Gates (Microsoft's Founder) from making money.
Usually when people get something for nothing they get pretty much what they paid for - something almost worthless. The surprising thing about Linux is that it is actually a very good operating system, better in many ways (and some would say most ways) to Windows.
The quality of the system is a clear demonstration that some leftists are actually intelligent, albeit misguided.