Well, I have no doubt that Al Nagler likes to sell eyepieces and telescopes but I have difficulty seeing any sinister implications here.
I found those quotes on the Tele Vue website in the advice section;
http://www.televue.com/engine/TV3b_page.asp?id=154
My impression is that there is no harm in using a refractor with exit pupils larger then 7mm if you choose to do so.
If you only have one telescope and it is a refractor then it has that extra level of functionality in being able to achieve wider fields by lowering the magnification.
If I want wider fields than the 3 degrees available in the 6" f5 Jaegers with 31mm Nagler (25x, 6mm exit pupil) then I go to a TV60 with 24mm Panoptic (4.3 degrees, 15x, 4mm exit pupil) or binoculars.