The converse of that is if he was hoping that they weren't muslim is that he was hoping they were something else. What else? Going by his fellow liberals' responses he was hoping that they were white conservative NRA and tea party members.
Truth has not mattered to the left for a very long time. It amazes me that our society ignores facts and goes with feelings - that the false narratives of the left on race, government spending, guns, etc. are accepted as truth when someone with an IQ over room temperture could see through their BS in a heartbeat. Very depressing.
No matter how many times that worldview is proven false by reality, its still the worldview he wants to cling to.