Absolutely not. People who take advantage of social mores to force interactions for commercial purposes are not entitled to the same grace and kindness you'd extend to a normal person.

This is why it's entirely okay to just shut the door on salesmen, or just hang up on cold callers. Indeed, that is actually the BEST way, because anything you say or do besides that will be used, by a skilled salesperson, to try and pry open a longer interaction.

These people are operating in bad faith, and should be treated accordingly.