Which game? I don't agree with the position of the person to whom you are responding, but there's almost certainly much more optimization put into the Windows version.
Why is “much more optimization” a limitation? What is preventing devs from optimizing the linux version? If the OS is more performant that should require less effort, no?
Windows absolutely dwarfs Linux when it comes to gaming market share. Game developers will factor in return on investment and therefore a proportional amount time will be spent on optimizing the Linux port.