To understand why some on the left defend Islam, I can only conclude it is a mutual hatred of America and all it stands for in terms of western values. It is helpful for the liberal left to try and portray muslims as an oppressed minority. It has been noted that "regressive leftists" in the West are "willfully blind" to the fact that jihadists and Islamists make up a significant portion (20% is estimated) of the global Muslim community and the minority Muslim communities within the West, even though these factions are opposed to liberal values such as individual autonomy, freedom of expression, democracy, women's rights, gay rights, etc.
Some have denounced the paradoxically illiberal, isolationist and censuring attitude towards any criticism of this phenomenon, which they contend betrays universal liberal values and also abandons supporting and defending the most vulnerable liberal members living within the Muslim community such as women, homosexuals and "apostates".
In October 2015, the hero of the godless, Richard Dawkins "lamented regressive leftists who fail to understand they are anything but liberal when it comes to Islam". The interviewer noted a willingness to criticise anything except Islam, excusing it as "their culture", to which Dawkins responded: "Well, to hell with their culture".
For once, I find myself in the unusual position of agreeing with him!