Sunni attacks were more pronounced and barbaric. Abu Musab Al Zarqawi , a sectarian Sunni, deliberately attacked Shia to kick start a sectarian war. Do you expect the Shia to do nothing when Sunni militants keep blowing them up.
The Iran-Iraq war was instigated by Saddam and the GCC Arabs. Saddam used chemical weapons against Iran, and was quietly supported by the GCC and West.
Terrorist State is a politically biased term. China,Pakistan,India,Israel,Saudi,America etc.. will label any militant opposition to their agenda as terrorists. "Terrorist" is a worthless word. We can just as easily say Israel, America, China,Saudi,India,Pakistan,Britain are all terrorist states.