Or maybe it's because you ignore practical issues such as audience size, A/V equipment, convenience for potential participants, and so forth.
I simply know the difference between a church and a school. It's not my fault that others get so easily confused.
Fine, I'll make sure to tell those political, environmental, and other special-interest student groups that a school is no place for extracurricular activity of any kind, either. After all, a school is not a convention all. Or shall we just admit that you have a particular prejudice against Christian groups availing themselves of the same facilities available to other groups?
Dark Ages placemarker.
For an afterschool student discussion group?
What do you think you're going to need?
A 50K seat sports arena with a rock & roll soundstage and laser light-show equipment?
Sheesh. I'm unaware of any church that doesn't have some kind of classroom sized multi-purpose room that can accommodate 20~30 people or so. Overhead or slide/movie projectors are also readily available, or can easily be donated by members of the congregation. Optionally, such items can also be readily acquired if the group has a bake sale or car wash. Religious youth groups do it all the time. If you were ever affiliated with one, you wouldn't consider such minor inconveniences to be an insurmountable obstacle.