As hard as it may be, please put aside your pre-existing view of PETA for the moment and consider this strategy:
You’re running a group that is committed to bringing people over to position X. For various reasons, there’s a big population that is quite accustomed to not even thinking about the issues around position X.
Do you try to grab them with a reasoned argument in favor of position X? That might work for the part of the population who pay attention to reasoned arguments. But there are many people who have gotten surprisingly proficient at tuning out reasoned arguments. (Remote controls and computer mouses make it so easy for them to drift off to something less tiring.)
So you have to get their attention with something they don’t see every day — perhaps a young woman taking off her clothes. Then, once you have their attention, you can try to engage them on position X (and that may involve a bit of shock and/or emotional appeal, too).
As the head of this group trying to bring as many people as possible over to position X, should you be at all concerned that your attention-grabbing strategy is likely to alienate a good number of the people who came over to position X on the basis of reasoned arguments (say, because the attention-grabber runs deeply counter to position Y, which many of the folks who were rationally persuaded of the goodness of position X also hold)?
Or, is it fine to count on the reasoned arguments to keep the people who also hold position Y firmly in support of position X as well?