It's common sense based on observable realities. There are 1.5 billion Muslims in the world - about 1 in 5 people on the face of the Earth. If it were anywhere near the threat the propagandized hiding under their beds alt-right believes it is, there would be a constant barrage of terrorism and attacks. They've been bombarded by propaganda and had their minds compromised for the past 15 years to be terrified of them. I went to school with Muslims, work with some, some of my neighbours are Muslim. Muslims immigrate into my country regularly. There are no notable issues due to any of them being there.
It's a propaganda talking point that the 'left' adores Islam, assuredly there are some overtly fanatical people who lean left that do think that way. The right and left certainly have their fanatics, but if you're discussing the right of America or alt-right trash, they are overwhelmingly more fanatical in their beliefs than the left of their nation. The irony is they have more in common with Islamic fanatics than anywhere else in the world, consider the fanatics of Islam are far right, just as the fanatics of Christianity who want to strip people of their rights due to their religious beliefs.
The reality is that there are profoundly irrational people in this world, susceptible to being converted and turned into dangerous lunatics. This is separate from religion or political ideology and a fundamental weakness of these people. Their religion is an avenue into their already fractured minds to turn them crazy and drive them to destructive behaviour. Religion is inherently irrational and the three current day religious myths are all based on the mythologies of Middle Eastern goat herders who lived anywhere from about 1500 (Islam) to 2000 (Christianity) to 2500 (Jewish) years ago. I think there should also be some simple exercises in empathy that are performed to try and understand why there is hatred from regions like Iraq towards the West. About 400,000 were murdered in the last Iraq war from the bombs being dropped and related carnage of that invasion. Imagine you are sitting in your home and suddenly a bomb rips through the roof and incinerates your spouse, or this happens to someone else close to you. How are you going to feel about the entity that dropped that bomb ? It's high time the aggressive arrogant foreign policy decisions to meddle in that part of the world are giving some considerations. It's not reasonable to expect to slaughter large numbers of people in a region and act surprised when they resent those doing the slaughter. It created a breeding ground for people that fanatics could recruit and use for terror. It's not an apology for those who choose to become violent and attack others in retribution. They are making that choice and it is their responsibility. But those acts of aggression are giving fanatics a basis of hate on which to indoctrinate and recruit with.
So when far right propaganda victims start in on their rants that the left loves Islam I just laugh it off. I abhor all religion. It is a cancer on society and the current day Abrahamic myths should have been relegated to the dustbin of historical myths like the Greek mythological religions and Pagan myths that came before them. What I don't have time for is ostracizing or demonizing people because of their susceptibility to fairy tales about being able to escape death or that they are the chosen of some invisible deity that is spying on their every daily action and thought. They have the right to believe what they want, regardless of how foolish. You can look at some of the posts in this thread and see the fearful propagandized bed wetters that advocate taking away basic human rights from Muslims and treating them as subhuman. That is where I have my issue. Christianity is not under an attack of human rights in the West, whereas Islam is. So I have no issue speaking out against these fearful assholes, even if I deplore the dogma of Islam as much as I do the other two major religion's dogma. It's a common trait among the religious to think they are better than the other faiths, just due to the difference of faith and believing their myth is better than the other's.
I agree that Islam has not been moderated like Christianity has. I believe this is because there are still nation based theocracies with governing laws based on the faith. But the evidence does not support the claim that 1 in 5 people on this Earth are fundamentally a danger because of some silly fairy tale they prescribe to. The actual violent acts and number of people involved is so minuscule compared to that 1.5 billion number that the argument holds no weight. Everything used to prop up that bullshit is innuendo and fear-mongering. The hard numbers are the proof that it's bullshit.
1 in 3 American Christians believe the bible is the literal truth. Even knowing that, when I'm in America I'm not afraid of my wife being raped or seeing babies slaughtered in their cribs as is advocated in the old testament, because it takes a leap beyond the religious dogma, requiring someone in a very small minority whose mind is broken to actually act on the bullshit found in the religious books of fables.