This is a followup to the thread you linked, but I'll mention it here because it may be relevant to the current conversation.

I spent a little while with TheValliant (offsite) trying to pin down a definition of "manipulation"--specifically, to divide it from acceptable forms of nonverbal communication. The facets which came to mind immediately were "trying to get someone to do something they otherwise wouldn't have," which is clearly too broad, and "displaying exaggerated emotion," which is sometimes valid (when you're trying to communicate an emotion and your natural expression is too subtle). We got from there to "trying to make someone feel an emotion they otherwise wouldn't have," which still isn't right, because it covers gestures of affection.

What we eventually settled on was this: "Using emotion to bypass someone's normal decision-making process." That is, creating emotions in someone else for the purpose of getting them to do something. This phrasing also makes it pretty clear why we find it abhorrent: it's opening a back door into someone else's brain, and about as invasive as that makes it sound.

The reason I felt a need to pin it down is that TheValliant, like you, has a policy of not tolerating it under any circumstances, and it seemed to me that that required understanding what it was. So now I'm curious--does the above definition match the thing you hate?