It might be prudent to avoid associating rationality with particular people or social institutions.

There's always the risk that particular instances of rationality will result in disaster, or that Bad Guys will be painstakingly rational, and in the early stages, wouldn't want to suffer the fate of religions, which often take reputation hits when their followers do nasty things.

Rationality could be advertised as a morally neutral instrumental value, i.e., Better Living Through Rationality.

On the other hand, we could sell rationality as a tool for atheists, drug policy activists, and stockbrokers, and publicly associate with their successes.