There are cases where it is not needed. If you have been a customer of the bank for a long time, and you have a stable job, they can give you that amount without collateral, at least where I live.
There are many aspects of banks that I don't like, but asking for collateral is normal if they have doubts that you are going to pay back the loan. Check out the lending section of the forum. It's the same thing. Someone who is low rank won't get a loan if they don't give collateral. High rankers who participate in signature campaigns are usually given a loan because they have a repayment capacity and because if they don't repay the loan they would be red tagged and would lose their ability to participate in signature campaigns.