We have had our very special experience with language inciting hatred and promoting actions in gross violation of human rights.

The simple incitment of hatred is not the issue, unpleasant and unwelcome as it is. This incitement can be dealt with in all society - but only by having the freedom of expression to enable other opinions and (more importantly) facts to be aired. The special experience you refer to is a terrible lesson in how any dissenting voice is effectively silenced and what happens when it is.

In our culture/system, such language wouldn't have the law on its side even if this language was rhymed, sung or processed/refined in some other way to make it 'art'.

You must be referring here to your present system. This system may be understandable, given the circumstances, but perhaps not really desirable. If incitement or other plain, deliberate offensive and insulting intention is otherwise dressed-up or presented as art - it is usually quite easy to see through this and to deal with it (perhaps best as bad art) without risking the freedom of expression that is so vital.