When people are told to change their behavior, sometimes their response is just to say fuck off. How could we possibly expect compliance without codifying what they should comply with? How would you deal with conflicting values? As much as governments are the single largest cause of mass murders and deaths, this is the one thing they are good for: defining parameters.
I get about 10-15 spam calls a day, but I do have two business lines forwarded to my personal phone too. If I do answer a call from a number I don’t know because I’m expecting a call, and it turns out to be spam I just hang up immediately.