I think we can all blame Tele Vue for the continued use of the undercut whether or not they invented it. What I don't understand is why they continue to when well over 90% of their customers would like them to stop.
It's not even 90% in this thread, not sure where you are getting that idea. I agree with Jon, the undercut causes me no problems. Using an equatorial mount I often find the diagonal pointing at the ground after a slew so I can see its utility.
Not sure why you would blame TV; I've seen undercuts on a variety of premium and nonpremium brands, including Zeiss.