"if it is trivial, why lie about it?"

Quite. And the fact that he did so, is possibly more concerning than the initial "flashing" episode. What people in power choose to do privately is important when what they choose to do privately (or not so privately in this case) has potential consequences for everyone else. The fact that he lied indicates that he wanted to keepthis matter a secret. Sexual secrets are good blackmail material. If you want to run the world, but are worried that the people you need to love you in order to run the world, don't like men who dance the can-can, then it's probably best not to dance the can-can in public and don't send pictures of yourself dancing the can-can in private to strangers who will make it public, over the internet either.