That churches are locking out politicians from speaking from inside places of worship is good news for faith practice. Let's begin from the outside. Parliament has a golden rule that "no stranger" may enter when it is in session. Even visiting presidents and other dignitaries must have a special reason to sit in Parliament or address it. The very fact that Parliament, a secular public space, is given such importance reminds us that protected space has meaning. A symbolic meaning.
When politicians roam from one church to another, it tells of their intentions to use churches for political ends. Of course, anyone is welcome to worship wherever they choose. However, intentions matter. Presidents Daniel arap Moi and Mwai Kibaki had more or less known places where they would worship. Yes, they could go to other places, but it was outside tradition. And that is how it should be.