Church or State

Maybe It's just that I do not understand what the separation of church in state means, or maybe the line has been smeared in the media.  When the pastor of the prominent Trinity Church of Christ made a sermon to his Congregation concerning Obama and Clinton the whole nation flipped out, but why?  Why does it matter what this Reverend preaches to his people f there is a tr separation of church and state.  No one gets upset when he preaches about the resurrection, or how Eve tempted Adam in the garden of Eden.  Are churches not allowed to speak on politics, who made that a rule?  Because of this Obama was forced to leave his church because he has to run a clean campaign.  People will find anything to destroy their opposition, but to go as far as tearing apart a church, and having the media hassle congregation members on their way in and out of service is ridiculous.  Can we for once focus on the issues for once and not what is being preached at the 10:00 am service at church.