The port to Linux will happen later. I forget the exact episode Casey justifies this but basically the problem for game developers is that every other platform

The port to Linux will happen later. I forget the exact episode Casey justifies this but basically the problem for game developers is that every other platform other than Window is not a good target platform if you want to stay in business. So he's showing people how to target Windows first and will show us how to port later. Just go look at the Steam hardware survey to find out why.