The original comment was saying that Google is able to perform anti-competitively because they control the most popular browser.
The followup (which I responded to) is saying that the existence of Windows as the most popular OS, and Microsoft’s control over the default browser there, mitigates this anti-competitive potential.
The fact that Windows is not the most popular OS (and that, in fact, the most popular OS is controlled by Google) undermines that argument.
Linux is not the most popular OS in any context that includes doing searches with the thing, unless you include Android, but Android just uses Linux for the kernel mostly, and an OS is more than a kernel.