The most disgusting thing that I have noticed is the deep and abiding love that leftists have for jihadis.
There is no rational reason for that love.
I will take a stab at why this love exists.
Leftism and jihadism are both totalitarian world-control ideologies.
Both hate Christianity and Judaism.
Both require suspension of rational thinking.
Both are against human nature.
You're not alone in thinking that this attraction is some twisted application of "the enemy of my enemy is my friend." (Never mind what those jihadis, when they come to power, would do to Unitarian lesbians who don't want to wear burqas.)
Oh you should hear the leftists talking about the “poor downtrodden Palistinians” who are at the mercy of the evil Joooooooooooooooooooos and the stupid Methodists who let them come present their claptrap at their meetings, along with references to the “evil Jooooooooooooooooooooooooos” as “dogs”.
Well, let me tell you, they thought they had a mutual admiration society there to present their lies to, but I gave them what for right in front of everybody and challenged them blow by blow.
You got it. Hitler found that the best Nazi recruits came from converting Communists.
You essentially have a spectrum. At one end you have the ideas of individual liberty and individuals being free to pursue their own goals, and at the other end you have the idea that the individual is the property of the Group (whether that group is the Islamic Ummah or the Communist State).