'The Muppets Take Manhattan' was released in 1984. Not, as Oliver says, in 1977.
Son of Sam didn't particularly target blondes, women, couples, or people in cars.
The thing about taking orders from a dog is that they aren't that specific.
SoS also failed to kill a majority of his victims, and was spotted at the scenes almost every time, so wasn't the terrifying killer stalking the streets people make out he was.