I guess separation of church and state is an institutional/legal feature. The way the people with the institutional jobs carry themselves isn't necessarily, but that doesn't make it illegal. It does make it frowned upon by the public be it when it mixes politics and religion (in Europe) or when it doesn't (in the US).

If you are not convinced, try it on someone who has not been entirely debauched by economics. — Piero Sraffa