From R. Adlerstein at Cross Currents:
Should Jews actively promote Jewish values to the rest of the world? For two millennia, there was not much of a question. No one would listen. Today in the West we have the ability to speak our minds, and often a large audience of those who believe that Jews have access to a treasure-trove of Divinely communicated wisdom. They are open to, and invite, our sharing it with them.
This is where the debate begins, not ends. Some believe that anything we say will in time be used against us, as it always was. Our stance towards others should be respectful and cooperative – but not educative.
Others believe the very opposite. It is more dangerous, they believe, to allow a world to plunge headlong into moral darkness. Besides, we have a Torah imperative to create universal respect for G-d (see Rambam in Sefer HaMitzvos, Positive Mitzvos #3). How better to do it than by showcasing the power of His teaching?
Probably by temperament more than anything else, I lean to the latter position.