We "defend" the office of the POTUS because that is what the Bible says to do. You may find his behavior AT PRESENT distasteful and annoying, but since his inauguration, I am not aware of a specific action that would demand a Christian to consider immoral. As far as his past sins, we all have them, and we probably all ask to be forgiven of them in some sense, or perhaps we don't. But we will not "condemn" Trump for private sins he has committed in the past, or even in the present as that is between he and God. If Donald Trump committed an act similar to Slick Willy, I am sure your demands for outcry would be met, but at present Christians are behaving just as they are told to.