I rode home 'falling down' drunk a few years ago. It was easier to ride than walk. Not too swift, but we do stupid things when we are teenagers and most of us survive.

That said, I would never do that again. I don't really drink anymore anyways so it's a non-issue now.

To answer your question, no I don't think that biking instead of driving drunk is morally 'better', even if it does endanger others less (note I said 'if').