It looks "perfect" because of a combination of anti-aliasing and high density. But zoom in on a repeating pattern of 1dp lines, and you will see that some are aliased and some are not if your display's density is not an integer multiple of 160dpi (mdpi).
But Android can do this everywhere because everything draws to a Skia canvas under the hood (well, HWComposer/SurfaceFlinger, but basically Skia). Desktop operating systems don't have the same luxury. MacOS and Gnome render at 2x and downscale the entire frame, which produces decent results on high-density displays but look blurry otherwise. I have no idea what Windows does but it sounds like it's a mess.
Doesn't disabling anti-aliasing make things look worse? Unintentional and random jagged lines never look right.
The original claim is that turning off anti-aliasing would make things look better, and not that it looks bad but not that bad.
Even in high res displays, isn't it true that anti-aliasing makes things look better?
Generally anti-aliasing is a trade off between pixelation, blurriness, and performance. The better the anti-aliasing and the higher the pixel count the slower the performance - this can be an issue and some GUI applications like some IDE's at high DPI's. Faster antialiasing methods will look worse.
In an ideal world a high enough pixel density would mean the apparent pixelation is so low that anti-aliasing isn't necessary. Generally anti-aliasing means more blurry - although the amount of blur might not be an issue for you, it depends. The higher the DPI the less pixels that need to be "guessed" which gives you better precision, which is especially useful for vector graphics like text that have theoretically infinite precision.
It really depends on how you define "better". Generally for text specifically I think most people prefer sharpness. This, combined with the much higher DPI display's we have nowadays I think we're at the point where for many people including myself, text looks better without antialiasing. Personally I think it's easier to read.
tl;dr - it depends on how you define "better". At very high DPI's I think we're at a point where many people prefer the sharpness provided by the lack of AA compared to the artifacts that are now relatively tiny thanks to the high DPI. Also in some applications like Intellij I also have had performance issues with AA at high DPI's.