Actually this makes sense if you think it through.
One of the key indicators lenders are looking for is a change in your financial situation, which they use your behavior as a proxy.
If you are routinely paying off all your cards, and suddenly you want to spend $100k, it's fishy because it hints at something going on.
Maybe a sudden medical diagnosis will push you into bankruptcy.
Maybe a lay off will mean you'll borrow as much as possible before missing payments and going into bankruptcy
Maybe you just want to buy something expensive over a few months, and are not a credit risk.
The point is the banks can't know, so they may make the choice of not taking a chance (because someone who suddenly takes on debt could have heads or tails kinds of prospects)