No, I don't agree.   Manipulation of photography is a perfectly valid art-form, BUT the degree of manipulation potentially diminishes the right of the eventual  image to be regarded as a true photograph.   Photographers may manipulate their work as much as they like, naturally, but that manipulation can soon go beyond the point where the image genuinely represents what was in front of the camera.   Now, the magistrates' courts may refer to the results as "evidence" and the photographers may refer to their "art", but I don't think anyone can legitimately describe a heavily doctored picture as a "photograph".