The stamp costs them money.
The printing and envelopes cost them money.
The administration costs them a bob or two.
Then there is the follow up by an individual that comes in a private car and the printed materials they post when they don't get an answer - more cash.
Is all this trouble worth it from them?
Its a form of harassment to me.
I don't get too upset by it but I don't like putting their rubbish in the bin because its the Earth's resources that could be put to better use.
I don't watch their drivel and I certainly don't want to connect with these people in any way.