I'm not sure whether or not these 4 are appointees but as part of the process Issa first has to impugn the investigative report which means he has to impugn those responsible for overseeing the report, the two highest level careerists, Amb Pickering and Admiral Mullen.
The problem with this is that Pickering is held in higher esteem than Issa.
Which brings into issue Pickering's testimony to the committee. Issa wanted Pickering to testify behind closed doors and Pickering was insisting on testifying publicly. In the end, Issa threatened Pickering with a subpoena and Pickering agreed to testify behind closed doors.
Issa tells the press that he wants the private testimony because he is concerned that some of it might be classified, and that he(Issa) will conduct a second public interview of Pickering..
Of course he didn't have the second public interview of Pickering and everybody knows why. He wanted to edit Pickering's testimony so that he(Issa) could select what part of it would be made public.
Which explains why the general public is ignoring Issa.