I assume you're not on the Do Not Call list? Afterall, those telemarketers are just capitalists trying to make a buck. They probably even have a genuine interest in lowering your credit card rate.
The way I see it, the people in my locality have decided we are on a town wide Do Not Call list. There are ways to get my business that do not involve disturbing me in my home, e.g. leaflet my door, send me a piece of mail, walk with your shovel down the middle of the street, just don't interrupt me by knocking on my door and expect me to do business with you.
You are right. You’ve convinced me. The cops should have just executed these kids on the spot...