In the interests of clarity, I should mention that the "Silurians" he's referring to are a Celtic tribe, not the Doctor Who villains.
Propaganda is a fine craft. This is why there are entire books devoted to the propaganda art of Nazi Germany and Soviet Russia: a good propaganda poster can be admired no matter how reprehensible the regime that commissioned it.
At the other end of the scale, we get bad propaganda art. Stuff that only somebody who already agrees with the cause in question could like - and even then, it is easy to imagine the hearts of the rank and file sinking as they see what their boss has come up with next.
For example, consider the artwork of the Welsh nationalist Gethin ap Gruffydd. I won't comment further, I'll let the images speak for themselves...