Perhaps Draco's reasoning for getting involved with the Resistance made a little bit of sense. He would never rise high up in the ranks. None of the respectable families wanted him anywhere near their daughters. Tracking was the only task he could really perform because most of the other jobs and positions were taken. It was fortunate for him that he was talented. Even if he wasn't, he would've been allowed to continue for no other reason than no one knew what to do with him. Some might have even hoped he would get lost on a mission and never return.