It's not new seeing this, because I'm the recent past I have seen people turn out victims of what they usually advised people against probably because bat some point they were constrained and could no longer stay disciplined well enough to adhere to the advise they even give out.
Borrowing to gamble is definitely not something any One should consider at any point, this is because of the too many uncertainties attached to gambling, you almost can't tell when you are going to turn out lucky with the casino and if it turns out you aren't Lucky especially when you stakes the money you borrowed it becomes a problem for you because you will have to pay back your loan regardless of the circumstances that befell you.
Some people are also hypocritical and are quick to give advise that likely wasn’t asked for or wanted. It’s very easy to give out advice but a little difficult to follow our own advice ourselves. And people are guilty of doing this. Also, like you noted, some people let the urge for their gambling habit get the better of them and they go borrowing to gamble in hopes of winning some more money.
That’s how loans work. An individual takes out a loan from wherever. Gambles with it and loses. He has lost out in his bets and now, he has a debt hanging over his head. The lender only cares about getting his money.