I agree that what constitutes the "top" or "front" of a part can be arbitrary. But for a lot of parts there are usually logical choices. If a part has an obvious top and bottom, front and back, I usually try to model it that way (so the top is what shows when in the top view, the front is what shows when in the front view, etc). I expect that's what most people do, as it makes the modeling a little easier. When doing this the drawing views normally correspond as well. So having default drawing labels that reflect this can be convenient. The CAD package I used before had that, and I find I miss it in SE. Not a big deal though.
Thanks,
Pat