Borrowers with poor credit ratings are sometimes people who can’t afford higher interest payments. At first this seems like an unfair system which favors the wealthy, but that’s not true.
Wealthy people have to earn their credit ratings through responsible use of borrowing. Everyone earns their credit rating this way, regardless of net worth. Some rich people are irresponsible about initiating and repaying their debts, earning them terrible credit ratings. Borrowers of very limited wealth can be very responsible when taking out loans and repaying them, earning them very good credit ratings.
Credit ratings don’t measure wealth at all, they measure financially responsible vs. irresponsible use of borrowing. Businesses have credit ratings of their own too, and they work the same way. A good credit rating means you will pay less interest when borrowing money.