I think most of it falls onto that people will take beautiful military rifles in pristine condition. Then try and 'modernize' it and make some errors, ending with a Frankenstein looking shell of its former glory. So it's not so much the good ones (like wyosmith's) that people have issues with. It's the ones where you look at it and literally say "what the hell is that?" that people start raging.
When I die better bury me deep, two .45s layin' at my feet,
An M16 across my chest, tell Chesty Puller I did my best