It’s not “dubious”. It clearly improves readability of text on most non-hidpi displays.
Most people don’t have “retina” displays. For most people this is probably preferable.
I don't like the font rendering on macOS, it is mostly OK now that we have very high DPI displays, but at a lower res it is kind of blurry.
IMHO the font rendering on Windows is excellent.
On low dpi screens, yes, it has always been a strength of Windows. Too bad that most apps nowadays are using the awful and blurry Chrome font rendering.
What do you find dubious about pixel boundary alignment?
As a side note, please note Macs don't even offer a means of turning off aliasing anymore, which for folks like myself has serious implications for eye focus under some conditions. For all its faults, ClearType and similar rendering solutions at least allow me to tweak it to both my comfort level and even monitor pixel arrangement.
I get that some people prefer it but a lot of people don't and it's frustrating to be stuck with it. My thinking is that unless there's clearly one best way, and if it's something people have strong opinions about, then a switch or knob to adjust is a good idea.