Why don't other people subscribe to your religious beliefs (or lack thereof)?

[Okay, maybe Mike Johnson is a competent parliamentarian.]

Because the details of Christianity can't be arrived at through natural reason alone and naturally some/many people will find the arguments-from-faith for them unconvincing.

Alternative answer: Because many Christians behave in exceptionally shabby ways, especially to disadvantaged groups in countries in which it's the traditionally hegemonic religion, and naturally this puts people off.