I can’t say anything about what they wore before and what they are wearing more recently. However, when it comes to calling someone religious, I’ve found that to be a very relative term–to be a bit more specific, I’ve heard it used by people to describe anyone who is more practicing of religious injunctions than them. Much like the term mullah.
Also, if a person is seen to be outwardly religious by wearing the clothing associated with that image, then the assumption of those looking at them would be that they are doing the things you would expect from the faithful and spiritual. Now if a person were known to just wear religious clothing and not pray and not observe religious obligations, then nobody would think that they’re religious. If they are frauds, it is not our problem, that is between them and Allah.