Why bother providing an "Antialias Guides and Paths" setting if it's going to look this bad when projected on a dark background? Yes, this is with that setting ENABLED:
It's not quite as unacceptably nasty when the path is dark on a light background, but it's still a good ways off perfection!
Did someone just eyeball this when implementing it? Do you folks at Adobe actually provide your employees with decent monitors, and teach them about things like gamma and how colors mix together?
If Photoshop should not be held accountable for being pixel-perfect, what application should be? This is not even close enough for government work!
Here's the PSD file with which you can generate the above if you'd like to reproduce the appearance shown...
Edit: Just to show that it can be done well, consider these two images, which I did by stroking the path in linear space.