It's just a natural extension of the techniques that PR firms (or before the 1940s, propagandists) have been using for centuries.

There's not really any similar techniques there, except that the tactics are a bit slimy. It's not like you can make an appeal to Google's Pathos.

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.

No it's totally different. Apple ran ads against Microsoft. They didn't prevent people from finding Microsoft's site on a search engine.