Lots of people file grievance complaints about lawyers. One of the quirks of our system is that there is no standing requirement to become a complainant against a lawyer in a discipline case.
Unlike malpractice, there is no requirement in lawyer discipline that the misconduct have caused any harm to the complainant. Nor is there any requirement that the complainant necessarily have an attorney-client relationship with the lawyer. Theoretically, someone walking past a courtroom and observing me struggling to examine a witness or stumbling my way through an argument might file a complaint that I was incompetent, and I would have to answer it, even though my client won the case and thought I did a great job.