Sure. About ten years ago, David Horowitz explained it in his book, Unholy Alliance . To Progs, the US stands in the way of world socialism. Since it is immoral to stand in the way of world socialism, any and all weapons and tactics to take down the US is a positive social good.
Since shariah rejects our founding principles, the Left/Muslim alliance makes perfect sense.
There is also the prevalence of Islamic socialism, which makes them “fellow travelers” in that sense.