see unfortunately the tv has given you nightmares
that dog has basiclly been given no training and brought up like a guard dog and given a few slaps for his trouble so that has been bred into him if you ask me the owner should be locked up as i think thats more cruel than having the tail docked
i have 2 adult rotties at home and they are as soppy as anything mate yeah they do bark when people come in etc so does every dog that dont know someone but its down to the owner to have trained it well
unfortunately rottweilers have a very bad name for such a wrong reason