> I have only ever seen one piece of antialised pixelart
You haven't seen a lot of pixel art then. Just visit Pixel Joint [1] (a well-known community) and on the homepage (which is updated all the time) you'll already see a few. One of the most distinguished members even has a popular "tutorial" [2] that discusses this and other techniques.
If you're interested, there's also Pixelation [3], a community where people discuss techniques in depth.
In short, anti-aliasing can be done by hand and using a low color count. There's also "index painting", something that many "hardcore" pixel artists consider cheating, but which creates the style without manual work [4].
The point others make is true, though: The sharpness of newer screens ultimately reduces their visual appeal (although there are people who actually prefer them).
[2] https://pixeljoint.com/forum/forum_posts.asp?TID=11299&PID=1...
[4] http://danfessler.com/blog/hd-index-painting-in-photoshop