You get treated like you are an idiot by someone that isn't very educated.
They are literally just ripping people off. This is how it works, they know of positions that need to be filled FOR OTHER COMPANIES And then they look around for people that qualify. If they find someone they contact them, REFUSE TO TELL THEM HOW MUCH MONEY THEY WILL MAKE and then if they are somehow still interested in the job they have them fill out a job application which is A COPY FROM THE OTHER COMPANY'S SITE. After you fill out the job application they simply submit the same information to the company actually hiring people. Then if you are hired they take a substantial cut out of your salary.
So you lose $10k+ a year so that you can fill out an application and have them fill out the same application with your information on the actual hiring company's site (Known as the prime).
Is it really worth $10k+ to have them do what you can do yourself? This is why they refuse to tell you how much you will make, you don't know until after you are hired and then they have to take out their insanely high finders fee. These aren't recruiters, these are middlemen that take advantage of people that don't know better.