I'm sure many med students contribute very little, but there most certainly some who do a lot more than just "monkey work." I'm sorry that you haven't seen this first-hand. Perhaps you're basing your conclusions on an inappropriate analysis; too small a sample size (how many students have honestly told you what they do?), selection bias (those doing clinical research avoid you and your ignorant comments), time bias (it can take a while to get an article published), loss to follow up (those doing good research get thell hell out of where ever it is that you are), misclassification (do you call really good clinical research "basic research"?)
As if there aren't tons of students being a lab monkey? I suspect there are tons more students acting as basic research slaves than clinical research slaves.
To call basic research more "hardcore" than other types is just ignorant. The theoretical thinking required in much of clinical research, clinical epidemiology, and straight-up epidemiology is much more difficult than most (all?) of that required in the basic sciences (at least in the life sciences). G-protein signalling is complicated, but it's pretty straight forward stuff.
Not many (regardless of what type of research it is), which is why it's impressive.
Experienced people struggle with good articles in any field.
Sure, some students get put on papers for just doing grunt work. But there are many who make meaningful contributions, and leave medical school ready to go into residencies and fellowships ready to continue doing good research, and eventually into academic jobs.