I think the OS is pretty irrelevant here. A CSS directive has been added to tell the font renderer – wherever that responsibility lies – to render text without any antialiasing, and the results are poor. It seems incorrect to me to blame the OS font rendering for doing what it has been told to do.
The only justification for the change seems to be one person preferring it, and one link to a blog post from 2012 about why this setting should be used when rendering light text on a dark background on low-DPI screens (which is fairly irrelevant to a dark-on-light website’s CSS settings for high-DPI screens).
Why is this the way it is?