KJ chusid – you are well-intentioned and I can appreciate the point you are trying to make, but IMO you are nonetheless mistaken. There are chassidim who have acted improperly in inappropriate places, and their clothing and manner of speech did not deter them at all, unfortunately.
In my experience, I have learned that it is not a good thing to generalize about something in absolute terms, because often those things can be easily disproved. It is not the Yiddish that is the saving factor, it is our implementation of what we learn in the Torah, in our own personal lives, that sets us apart.