Incompetence is indeed a reason to withdraw, but... Willfully and knowingly misrepresenting things isn't incompetence. It's an ethics thing. It's actually possible for a lawyer to be disbarred for providing evidence of any kind when they know or should know the evidence is false, or they do not act to inform the court of the falsity as soon as they discover it to be false. Has Lemoine informed the court about certain false statements in the affidavits that he is most certainly aware of? Like certain statements that are in conflict with reality which he wanted to use as evidence of Vics behavior?
Luckily for him, I only know of one Texas lawyer that got disbarred for knowingly submitting perjury in the form of affidavits, and that guy had been doing it for years. Lemoine might get a warning though, if Ty or the court decides to submit an ethics complaint.