The song itself mainly is about Terrorism in the 20th and 21st century. And the hypocrisy of the groups which commit terrorism. As its main points. However the song itself is about terrorism as a whole through history.
It points this out in the first main lines of 'Claim you're just, killing women and children'
The pause in the line is important as it point out the fact that despite most groups saying there actions are 'just' and for a 'good cause' the main victims of terror attacks are mainly women and children.
I'd also like to make a note to read the line as 'Claim you're just killing women and children' Which it is often sang as which gives a different meaning to the lyric.

The latter part of the song also is about the war on terror. Mainly in the lines;
'Captured in all your lies, fear is in your eyes
Creature who has gone insane, your war is in vain
Trapped in a cage of stone,... (Continues)