Conditional Separation of Church and State?

A Republican can’t go within a block of a church without liberals making a stink about the so-called “separation of church and state.” Liberal pundits will go on TV criticizing, railing against evangelicals and the Religious Right…

So, why is it that Barack Obama can go to an Atlanta church (MLK Jr.’s church) and make a political speech, and I’m not seeing anyone making the same criticisms? Is it okay to embrace and to reach out to churchgoers if you’re a Democrat who supports gay “marriage” and abortion?