I'm sure some of them are idiots. I'm also sure there are some people who needed a car to work, catalytic converter went out and they needed to find the cheapest possible way to pass emissions and keep getting to work.
I know that because I'm about to drop a thousand or 2 on my catalytic converter, which I'll have to install myself to save money, to pass emissions. Luckily, I can budget well and every car repair known to man is on YouTube