Fair enough if PETA didn't seriously mean it...
But, perhaps if they hadn't done quite so many fuckwitted things in the past, we'd find it easier to know when they're joking. I sense if say, the WWF had sent in a humane fly catcher with a witty note, it would have been reported as a piece of humour, while still getting across the message that 'all living things are worthwhile' without coming across as daft.
On the flipside, the media are well known for reporting complete lies, just to give people stuff to talk about.
For example, the Daily Mail and many of the 'EU rulings' about Britain being banned from selling bananas that are too bendy, and other such nonsense.
It gets people talking, and gets people thinking that the newspaper's views are right, yet they seem to get away with it.