I have no knowledge or opinion on this specific situation, but I'm curious about two points:
- why is their minority status relevant? what difference would it make if the majority of the population practiced that belief that way? would it then be any more or less acceptable?
- why does it disturb you that different demographic groups get to attend different worship services, in their practices? is there any harm in that? would it make a difference for you if they partitioned their worship services by age ranges, by marital status, by offspring-having, by (claiming to) holding certain variant beliefs, by how often they attend the service, by which language/s they speak or learn? does it also disturb you that different genders are segregated to different restrooms and locker rooms, in so many cultures?

CC: @gugurumbe@mastouille.fr