Were you suggesting that non-Islamist terrorist groups were not significant terrorists in the past?
Non-Islamist groups WERE sugnificant, but where is the Klan now? Where is IRA?
The Klan is still here, although fortunately it does not have the power it once had. Unfortunately, it competes with other white supremacist groups for membership these days. The Provisional IRA surrendered its weapons a few years back. Other IRA splinter groups continue their work as terrorists. FARC is still around, as are the LTTE. There is absolutely no reason to suspect that Islamist groups will be the only significant terrorists for the rest of time.
Your way of reasoning resembles involving the Incvisition and Western Hemisphere slavery in discussion of the Crusades... confortably forgetting that both took place several centuries AFTER the event in question.
If you can't see how the Crusades -- campaigns against the non-Christian control of the Holy Land -- is related to the Inquisition, then you have no business posting here. If you can't see how the Crusades -- which held that non-Christian, non-Europeans did not have the same rights that Christian Europeans had -- are related to the enslavement of millions of non-Christian Africans and non-Christian Indians in the Western Hemisphere, you have no business posting here. Violence against infidels (including the Eastern Orthodox) was considered justified and laudable during the crusades, an attitude Europeans held towards infidels for centuries after and carried with them to the Americas.
I have no business posting TO YOU. It was clear long time ago, so I can blame only myself for the waste of time.
Just a good-bye remark:
a) all the terrorist groups, Muslim or other, which are now out of business are out of business as a result of solid ass-kicking;
b) Islam is a religion, not ethnic or national group, the names Brasilians give to different species of Levantines notwithstanding.
Be well!