I don't care what religion they belong to when they come to my door. I just politely tell them I'm not interested. If they insist I take some of their pamphlets, I do, but reaffirm that I'm not interested.
No need to be rude, unless you're an unmitigated ****.
And saying, "No, thank you. I'm, not interested." probably takes you far less time than it took for MrS to type out his silly rant. Mormons and witnesses "proselytize" door-to-door. Big whoop! They also understand how to respond to a polite, "No, thank you." And witnesses, BTW, keep records of every house visited. After a few refusals over a year or two, they don't knock. I would not be surprised if the local Mormon stake does similarly.
As for that bogey-word, "proselytize", religious groups who claim to be Christians all recognize and try to follow a certain command given by Jesus: "Go, therefore, and make disciples of all peoples ...". That's reality, and folks like these DU-people aren't going to change it by whining.