Merry Christmas, Pierre. Welcome to the forum. We love having the input of someone who was never a JW. Thanks for showing up today.
When it comes to "organized" religion, JW's have the organized part down better than organized crime. There is a definite pecking order, lots of propaganda speeches and pep talks to keep the rank & file from getting off track. Some of the reasons JW's would give you for going from door to door probably would be something like love of neighbor, to sound the warning of the end/Armageddon, zeal for "the truth," or something similar. The truth is that JW's are watched and spied upon by one another and are under tremendous pressure to distribute literature and conduct so-called Bible studies to make new converts. Most of them are just like you, and, if they were honest with themselves, would rather do just about anything but knock on doors and intrude on people's family celebrations.
Many of us here were brought up as JW's while others were sucked in at a low point in our lives or because we did not feel connected with others in a positive way. The JW's give people a cause, something greater than themselves to devote themselves to. (See The True Believer by Eric Hoffer).
Try to be kind to the JW's. They're lost, with all of their hopes tied up in a corrupt organization. But while being kind, don't hesitate to plant some doubt in their minds about what they're doing.
Regards,
SandraC