I second what Fur God's Sake said -- they are unneeded middlemen, leeches who have a vested interest in NOT PAYING.
Just stop and think clearly about it for a minute: an industry whose sole purpose is to make a profit, while paying out cash to help people who are sick. The only way to guarantee a profit in such an industry is either to pay out as little as possible, or to jack the premiums up as high as possible.
Leeches, pure and simple.