Quirrel himself makes fun of the Dark Mark

Ah... no? Actually, the opposite of that.

"Division is weakness," said the Defense Professor. His hand closed into a tight fist. "Unity is strength. The Dark Lord understood that well, whatever his other follies; and he used that understanding to create the one simple invention that made him the most terrible Dark Lord in history. Your parents faced one Dark Lord. And fifty Death Eaters who were perfectly unified, knowing that any breach of their loyalty would be punished by death, that any slack or incompetence would be punished by pain. None could escape the Dark Lord's grasp once they took his Mark. And the Death Eaters agreed to take that terrible Mark because they knew that once they took it, they would be united, facing a divided land. One Dark Lord and fifty Death Eaters would have defeated an entire country, by the power of the Dark Mark."