Just as a data point: the emotional manipulation tactics (i.e graphic videos) were effective against me. (Mostly because I was unfamiliar with the process before. I didn't know what happened) They tend to be effective in people especially sensitive to graphic images, I think, but I realize that in general it's not a tremendously effective way across the population spectrum. If it was, everyone (or at least everyone who has watched those videos) would probably be vegetarian at this point. This is not the case.
Just as a data point: the emotional manipulation tactics (i.e) videos were effective against me.
As another data point, emotional manipulations tactics are HIGHLY counterproductive against me. I dislike being emotionally manipulated and when I see attempts to do so my attitude towards the cause worsens considerably.
I'm currently unconvinced either way on this matter. However, enough arguments have been raised that I think this is worth the time of every reader to think a good deal about.
http://nothingismere.com/2014/11/12/inhuman-altruism-inferential-gap-or-motivational-gap/