I used to be a JW in my youth (because that was the religion my parents taught me) so I may be able to provide some unbiased judgment here I hope.
I HATED having to go door to door, since I knew how annoying that was, particularly weekend mornings. Anyway, I felt compelled to do it because all the leaders or ‘elders’ encouraged us to do it and frowned upon on those who did not. I don’t remember exactly what part of the Bible says this, but they used to tell us “they are your responsibility, if you don’t warn them, their blood will be in your hands” Of course it does not say that literally but it is something like that.
I agree it is very disruptive but I don’t think it is necessary to go to extreme measures to get them to stop. I cannot speak for all JW in the world, but at least in my case, when someone told me thanks but no thanks, I thought to myself, well my work here is done, I did what I had to do.
I found LOTS of people with genuine interest, maybe they were doubting their religion or were just looking for something else, and that’s where I got into JW mode and Witnessed the hell out of them, because those people were worth my time.
The thing is, you may find people who live normal lives, spend their week at their jobs and go to church on Sunday, but you may also find fanatics who like to throw their religion in your face. I think all religions have these kind of people, and JW are no exception, but that does not mean all of them are like that.
Now, about knocking into uninvited houses, I agree it is very annoying, however their religion REQUIRES them to do it. For them, it’s just like going to church on Sunday. Why do we have to do it? Because God says so.
Sorry it is a bit long but I wanted to add my two cents here