This is the sort of image that, due to its graphic style, at first glance seems as if it will be easy to "get", perhaps propaganda for a cause or clever one-liner. But it's much weirder and more challenging than that. This is, after all, art.
Identical figures seem to march in step, reminiscent of a disciplined military force, implying some powerful leadership and strict code of conformity. They form a solid, intimidating wall, with sharp spikes of texture and shadows. At first, they seem an ominous force to contend with.
But, but... they're cute, little sheep! Even in their large numbers and harsh, dramatic lighting, they are undeniably those fuzzy, adorable creatures known for their gentle demeanor. That's why we so often encounter sheep in petting zoos.
The humor is further emphasized, and more questions are raised by the signs the sheep carry. The message, "UNPLEASENT THINGS ARENT NICE" is so obvious and vague (not to mention misspelled), that it is meaningless. It is kind of an everyman of slogans, the type often seen on bumper stickers or handmade signs in protests, which communicate nothing except to those who are in the know.
The image reminds me of a great dilemma for any would-be iconoclast, the black sheep who dares to question the status quo, and then longs to change things for the better. As an individual of average means, one person's efforts might be totally useless. But join a movement, and suddenly that same individual's efforts, though still small, can become effective. The problem? The group can never reflect the sophistication, the thoughtfulness, the unique vision of the individual. Journalists will catch on film or in writing the most radical sentiments (and worst misspellings), and suddenly every environmentalist is a violent thug who cares more about trees than the lives and safety of loggers; every tea-party supporter is a racist who thinks President Obama is both a Nazi and a communist. Worse yet, membership in a movement can create an echo-chamber. Extended immersion and isolation from other points of view slowly pushes opinions to the extremes. Eventually that which sounds perfectly obvious and reasonable to anyone in the know, sounds positively ludicrousness or incoherent to anyone else. The movement becomes, for all practical purposes, an army of slightly-scary, but mostly silly nutjobs. He or she who was once a black sheep with thoughtful and provoking ideas steps into the light as just another indistinguishable member of the herd.
That said, for better or for worse, there is power in numbers.