All of my work is printed uncropped. Here's why:
Many moons ago when I first was given my first point and shoot camera by my father, like most people I shot color and dropped off the rolls at the local chain store. I'd get back 24 or 36 4x6 prints in an hour. At the time I never knew only portions of a negative could be printed. So I learned from day one to make sure that what I wanted my print to look like was what I saw on my ground glass.
Several years later I took my first b&w course at a local college. I missed the day where the teacher went over darkroom basics and demonstrated the steps in making a print. So once again I didn't realize negatives could be cropped. Besides that, the stock guys would simply hand me full frame carrier when I would check out my equipment. By the time I finally learned of cropping I was thrilled! However, when I tried it on a few negatives, it really left me feeling that I was somehow ruining the picture I had intended. I guess I got set in my way of shooing for full frame and being the creature of habit that I am, I still continue to print full frame in both 35mm and 6x7 sizes. Recently, all the full frame carriers where checked out so they gave me a standard one (for 135 film). I put in a neg and looked at the projected image on my easel and knew this just wasn't going to work out so I checked the carrier back in and simply waited for a full frame one to be returned.
As to what I think of other people cropping their images, I don't think anything of it. If this is how they make the work match their standards and vision, then great. Robert Frank cropped many of his negatives when printing the photographs that make up "The Americans"; some only a very small part of the neg was printed. This is still one of my favorite photography books and Frank will always be one of my favorite photographers.
As far as printing the rebate edges, I kind of like how the 6x7 full frame carriers only show a slight jagged edge around the image rather then a black boarder. With 135, I usually don't mind the rebate edge printing black around my images, but there have been times when I wish this wasn't the case. At least the carriers at school do a good job of keeping the sprocket notches out of the frame (for the most part) and the film info. I can see where some may find printing like this pretentious and elitist, but as I mentioned above, I simply got into the habit of shooting and printing this way by default.