Public and Private

Andrew Sullivan explains why he blogged last week about Elena Kagan's sexual orientation:

I was caught between two very powerful impulses: the ethical desire not to say anything untrue or unverifiable and the ethical compulsion I felt to be totally honest with my readers about what I made of the passing scene from day to day....And I could not wait or duck. A columnist can do that; a blogger cannot. To have stopped myself asking of Kagan's orientation would have been, to my mind, something of a rupture of trust between me and Dish readers. It would have erected a barrier between my own thoughts and what I allowed to appear on the blog.

I don't get this. A compulsion not to simply parrot the conventional wisdom or pull your punches I understand. But isn't silence ever an option? There's no rule that says every passing thought has to be memorialized in a blog post, is there?