Some players think Heroic dungeons are too easy. Some think they're too hard. Some think they're appropriately challenging, but take too long to complete. None of these opinions makes a person "bad" or "casual" or any of those other single-word descriptors you listed; they make a person, well...a person, someone with unique experiences and expectations.
We know people feel differently about the current content and we're taking all that feedback into consideration. There's no need to try to pigeon-hole people or make them feel bad for holding an opinion that might be different from yours (or even ours).