For people who have debilitating social anxiety, yes, it does.
However, in general, the decision to answer or not answer a salesperson at your door is not about bravery. It is primarily about effort and annoyance.
The combination of "Is it really that hard to say "Selling something? Not interested, have a nice day!"?" and a condescending "Gotta be brave and interact with the world sometimes." rubbed me the wrong way.
It did me, as well. It smelled of someone projecting their insecurity onto the general public.