I think the observation is correct. I once have posted a similar observation about republican and loyalist songs, namely that (on the whole, not in each instance) the loyalists songs are more hateful than the republican songs.

I'd like to speculate now, in a more general way, why this may happen (not only in Northern Ireland, but in all places where there is a deep inequality between two groups of people. My speculation goes like this (commentaries asnd counterexamples invited):

The underprivileged (minorities mostly, but not necessarily, see SA) want to have the same rights and life chances and such a demand is so modest that singing (or writing) about it is an easy task and needs no hate propaganda about the other (privileged) group.

To write propaganda for the priviliged group is a much more demanding task. To say simply, we want everything to go our way like it always was so far, may be very close to the truth but just does not go down well with more neutral observers. There is a dearth of possible general human rights arguments (no one may ever lose a privileged and not earned position for instance?). So what can you talk about? There's always the last resort possibility to paint them as subhuman, devils, murderous bastards which (implicitely) makes the point that they may not be awarded with the full range of rights and chances.

That's a bit like with (real) criminals: They lose some rights like the right to vote, or the right to some offices, and no one thinks that's unfair for they deserve to be treated this way. To paint a whole group as criminals and to be hated subhumans tries to make it understandable (mostly to the own ingroup) that these brutes just may not be trusted with full rights and equal treatment.

Perhaps that's why there are so few if any good songs supporting the privileged against the onslaught of the wild. It is so damn difficult to argue in a convincing way against basic human rights like equal treatment.

Wolfgang