Steam reports 3.4% for linux and 2% for macos (last montg. This month numbers are probably hit by systematic measurement errors).

https://store.steampowered.com/hwsurvey/

Also, the 16% “unknown” in the graph you linked to implies huge error bars on macos vs linux!

That's desktop market share. I'm sure the comment you're replying to means overall usage including mobile and server, where Linux is far and away the leader.