It is a sad fact that all religions have produced more than their share of fanatics, continue to do so - and, regrettably, will forever do so.
Even the so-called "Christian" churches are not exactly squeaky clean in this matter, with such events as the Crusades, the Spanish Inquisition, forced conversions and the infliction of the Dark Ages on Europe by the effective banning of education, research and scholarship.
Conversely, Islam has not always been about the fire and sword / forced conversions / suppression of knowledge etc. that it has recently got a name for. Under Moorish rule in Spain, scholars were not only tolerated, they were warmly welcomed. During those years, the three centres of learning in the whole world were Baghdad, Constantinople, and Cordoba - two out of these three cities being under Moslem rule. This was at a time when the Roman Catholic Church suppressed learning (like another religion we are all here familiar with!)
Also, when the Ottoman Empire was at its peak under the Sultan Sulieman the Magnificent (i.e. during the 16th Century), he had himself instructed in Christianity, so as to better understand those of his subjects who were Christians. Under Turkish rule, the Greek Orthodox Church in Eastern Europe was permitted to continue as before - something the Roman Catholic Church would not permit in any of the lands in Western Europe.
What I have just said will stick in the craw of some who post here, but it does need saying, anyway!
It is not just Islam that needs villifying for its production of fanatics, all religion - without exception - is just as guilty.
Bill.