An answer
Firstly, I'm in total agreement with you when it comes to those who walk slowly on treadmills and don't even get the tiniest bit sweaty.

However, I too am one of those women who "just walks" on the treadmill. This is because firstly I have the world's shittiest joints and can't do anything vaguely resembling even moderate impact. Sometimes even normal walking hurts my knees. And secondly, because the purpose of cardio for me is weightloss, not to become the world's fastest runner. That is, for me the optimal workout is one that keeps my heartrate at around 70% of maximum, not around 90% which it would be if I ran. My trainer puts a heartrate monitor on me from time to time to tell me how fast and at what elevation I need to set the treadmill to get the right heartrate.

But again, I totally don't get the whole 'drive to the gym and then walk at a pace that would slow down my invalid grandmother' people. Especially when they're using the machine I want and not even getting anything out of it :(
(xanthine, Tue 14 Jul 2009, 5:03, Reply)