I understand that. But the argument that secularism and Christianity are both religions is an exercise in sophistry, easily demonstrated by the fact that the same definition of "religion" is not being applied to both.
I work in IT, and it's fairly common among programmers to speak of strict adherance to a particular programming methodology or structure as "religious". That doesn't mean that anyone went out and joined the Church of Python.
actually #4 can be applied to both, christianity and secularism fall under that definition.
you'll have to point where in ANY of the definition, require joining a "church".