With the rising prominence of sentiment analysis, named entity recognition, etc., I wouldn't rule out the possibility of appealing to Google's pathos in the near future. E.g. blog farms badmouthing competitors without even the hassle of building natural-looking links.
Morally it's absolutely no different than Apple running PC guy ads targeting Microsoft, Windows, and PC makers in general. It was a negative campaign meant to harm the competition by making fun of it.
Yes, because sabotaging your competitors with shady spamdexing practices fits most people's definition of "professional."