Are you really advocating for the plight of these poor scammers?
Regardless of the reality, I get the sentiment. Hey we built this system that can trap humans in an infinite social loop requiring either superhuman willpower or outright sociopathy to escape. But don't worry, we only use it on the bad people.
It’s unfortunate that some people need to do bad things to make a living but it’s an explanation of bad behavior, not a justification for it.
Mind you, I’m also sympathetic to the ways in which this practice could be abused.
Or, you can just hang up if you have your suspicions. I don't see this kind of banning particularly useful. If it gets sufficiently popular, telemarketers will just work around it in their scripts.