I guess it's because they're not actual robots, though the way they consistently hit T20 and their doubles is robotic at times.
This a good read on the pursuit of perfection in darts as well as other sports - NYT Darts
(you may be able to get round the paywall by opening it in an incognito...
Littler averaged just shy of 102 last night, and Humphries almost 109. Both fantastic but check out this list and see how mnay times Taylor pops up:
https://en.wikipedia.org/wiki/High_dart_average