My dad works in a factory that runs 24/7 with four twelve hour shifts. His pattern of days off means he works every other Sunday, every other Christmas, every other Good Friday, etc. If he fasted on Good Friday and refused to work on the Sabbath, he wouldn't be able to do his job. It is what it it is.
The classic example is an NFL referee whose religion won't let him work on Sundays. Just can't do it.
When I was in college in the early 90s, I worked for AT&T as an operator. Great job, great pay, no flexibility. Two 15 minute breaks, and a 30 minute lunch. Had to turn the light on if you went to the restroom, and wait for the light to go on before you went.... Sat side by side with several Muslim friends. They did not have a problem with AT&T's process and requirements.... Mid 90s worked in a call center, with pretty much the same inflexibility. No problems there either.
IMO, companies do not have a duty to go out of their way to appease all religions. So long as they treat everyone the same, I have no problem with this. Like separation of Church and State, Church and business don't have to be intertwined either.
My Muslim friends (very close to 3) back in the 90s were just happy to be here, loved the opportunity to get a US education, and respected the US culture. The only thing some of them struggled with was their attitude about and towards women. Outside of that, they did not feel the need to push for this, or complain about that. These days it seems everyone feels entitled to transform the US into something more aligned with the country or culture they left or took flight from.