I don't know which Catholic FReepers you observed, but I haven't observed any who are ignorant of Islam's implementation of its beliefs. For the record, this Catholic is quite aware of what the Muslims are up to.
As an aside, I even know non-FR Catholics who are well aware of reality. I attended a lecture by a Catholic priest who stated, in no uncertain terms, that we are in a spiritual war against Islam whether or not the politicians are willing to admit it.
I think to err on the side of spiritual warfare ignores two things:
(1) the militance we see at present is primarily communist radicalisation of Islam effected in large part thanks to the arrogance of the West and their falling hook, link and sinker for the sucker punch that was Israel.
(2) that we have far more in common with Peaceful, faithful Muslims than we do many of our own where issues of human life, marriage and family are concerned. It was a real blow to the Church -- she was seen as weak, conspiratorial, stupid, what have you -- when she pulled out of her partnership with Uncle Sam to engage in ostpolitick with communist nations.
Who better than the Church to recognize the Spiritual Warfare being waged almost exclusively for souls (particularly in the West) once the great purges and slaughters waned?
Yet she reached out to those people (and had a tremendous effect, I believe, having seen the fruits of faith blooming again after 80 years of militant atheist rule) because she realized the greater danger was coming from the West who -- as has been born out -- was preparing to wage world revolution by proxy. Not only moving the United States proper left but imposing its Culture of Death on the globe and conditioning folks to demand its precepts -- from abortion to euthanasia -- as "rights".
If we're going to talk spiritual warfare, let's not forget the Church is focused also squarely on the United States. Our population control, our rabid individualism, our "saving graces of western materialism" ... the way any objective observer had to conclude we were in league (to great extent) not only with the Chicoms we appeased, nourished and with whom we sought to "co-exist" but also the Soviets whose drug offensives and gramscian-marxist assault from within (at the break points that were academia, the media and government agencies and most-favored Interlock foundations and thinktanks) seemed to have the protection of the most powerful in the west.
Simply put, I'm not prepared to demonize Muslims en masse or ascribe to the heresy of Islam any powers it's actually assumed thanks only to the radicalizing by militant atheists from the East whose job was made infinitely easier by our assuming Israel's battles and our arrogant imposition of our "western values" (or lack thereof) on others.