Instead of looking at things backward, list the secular schools and apply for them.
As has been pointed out more than once, not everyone has that choice. Not that true secular schools are available in this country.
Otherwise feel free to be discriminated because of the private school you can't attend, the boy school your daughter can't attend, the grammar school your kid can't attend.
Those are completely different scenarios. Private schools are a complete choice, and grammar schools are supposedly meant for the more intelligent children of this country (although we all know they’re a bit of a farce as well). The schools you mention are very few and have no impact on the average child getting a school place when needed. Faith schools do.
You can't even argue that your non religious child cannot attend the faith school because they all accept non religious children AND you can remove them from the religious element (in a faith school.. because that makes sense)
But I don’t want my children going to a school that will indoctrinate them with nonsense, and why should they have to miss out on school time because of a faith they will not be part of? Why should children face a choice between isolation from their peers, or be a part of some charade? And to avoid all that, why should my children have a smaller selection of schools to apply to initially? Have to travel much further to get to?