They might be referring to when Apple removed subpixel antialiasing around ~2018. It caused some consternation at the time because there were still plenty of no

They might be referring to when Apple removed subpixel antialiasing around ~2018. It caused some consternation at the time because there were still plenty of non-retina Macbook Airs in service. While it technically works, macOS really is not meant for non-high DPI displays.