I say give the guy a break. To me, the song looks like it is written in the first person....the lyrics don't reflect Steve's personal beliefs, but it is written to show what "Johnny Jihad" believes.
A lot of songs are written that way.
You don't think that Johnny Cash is a murderer because he wrote Folsom Prison Blues", ("...I shot a man in Reno, just to watch him die...") do you?