That is the MO of some of these door to door sales groups. In my experience they are usually selling cleaning products.
They bring in a van full of sales people to an area and they have an aggressive approach and act indignant and insulted when you say no thanks no matter how polite you are. In fact the more polite you are I think the more aggressive the negative response.
Not sure if it is an intimidation tactic to make you reconsider to show that you are not a racist, unchristian, etc.
I have had it happen at least once each summer for several years in a row.
Last summer I had just come in from working my bees and answered the door in my full bee suit to one of these cleaning products guys with the now familiar pitch.
Just as he started his pitch I told him in a concerned tone that my yard is full of angry bees and suggested it my be wise to move along.
Worked like a charm.
Here is a KSL story from last year in Springville.
http://www.ksl.com/?nid=148&sid=29711534