For the most part, the replies to this thread are pretty much correct. However I want to add:
(1) The difficulty of ones graduate program isn't just about grades, but also about what they did. In terms of masters programs, there are usually two kinds: (a) masters by thesis, that is, one does research and writes a thesis to earn their masters degree, or (b) masters by exam, where you take an oral/written exam that covers all your courses. Choosing masters by thesis implies doing mandatory research, therefore despite taking "less" classes compared to undergrads, they are in effect working full time to get their research done on time. Doing masters by exam doesn't mean that these people aren't working or doing research either. Therefore this will be addressed by the adcoms.
Now, one also forgets that there are PhD students applying to med school as well. These people will be doing more research than a typical masters student. Some programs may require PhD students to take more classes too.
So that must be weighed in with their GPA. I for one take about 8 units of classes, and have 10 units of research. So I average about 18 units per quarter.
(2) To give an example of grad courses offered through my school (UC Davis). Grad level courses in pharmacology, physiology, pathology, med statistics, and molecular biology are ALL as hard or harder than the med school courses. There's not even a comparable course at the undergrad level. The med school faculty teach these courses, they use the same powerpoint slides, and we use the same texts. The exams are harder because they aren't multiple choice. We actually have to solve problems, rather than regurgitate information. Of course nothing wrong with the latter, since the med students have to prepare for Step I.
How do I know this? Because I've taken all these courses as a PhD candidate. When I was preparing for my qualifying exam, I used the med school course as review...and realized it was actually MORE watered down than my course! So to imply that grad school, at least my program is easy is to imply that UC Davis School of Medicine is also easy...which is of course false.
(3) We don't know what these people took as graduate students. Some may have just taken the BARE minimum and maintained a 4.0. That is quite obvious for adcoms. Others may take tons of grad level electives and done well. Then there are those like me, who took my core classes and take additional medical level and upper division undergrad level classes to boost my undergrad GPA. There is no way for someone to determine that X-profile on MDapplicants is one of these three kinds of people.
Anyway just something to think about.