Derech: I don’t think that is the reason why. The reason you can frequently spot them a mile away is that you also could have spotted them a mile away before they became frum. Because they were weird before they were frum, are weird when they are frum, and will be weird after they are frum.
They aren’t weird because they don’t know how to fit in; they don’t fit in because they are weird.
Anyone who has been involved in kiruv knows precisely what I am talking about.
(P.S. Please understand I am generalizing, and of course I am familiar with many, many, BT’s and geirim who do not fit into what I am discussing.)