Short answer: because none of them is the default in standard plotting tool.
There is so many alternative that it is hard to know which replacement you should pick. If you pick the wrong one you are a moron, if you stick with the bad default it's way less noticeable, even if it is a strictly worse choice.
The default issue is certainly keenly felt. My first scientific publication graphs were done with Jet. But since switching to some of the perceptually uniform ones (most often Viridis), I've never had a complaint.
But your point "if you stick with the bad it's way less noticeable" is understandable.
