Why borrowers pay loan origination fees???

Answer 1

It is the fee charged to a borrower for the processing and closing of the loan at an agreed upon interest rate. The origination fee is customarily 1% of the value of the loan amount. Does every loan have one? No. As the interest rate increases, the origination fee decreases.
http://www.alphaloans.com/content/faq.html#1

A loan origination fee is often charged by the lender to cover processing and account set-up charges.
http://www.acbankers.org/accounting/chapters/chapter13.htm

Answer 2

To help the lender make more money.