I have some experience in kiruv with Jews from the former Soviet Union. By the time someone gets to the point where they could be considered a ben Torah they would have already had enough guidance from a rav to know whether or not they’re halachically Jewish. We who are used to it don’t realize how complex being shomer Torah and mitzvos really is, and how completely it affects our lives. You have to be in the position of explaining things to someone who is starting from square one. I once had the experience of explaining to a bewildered beginning baal teshuva who was learning to keep Shabbos about the 39 melachos, and he breathed a sigh of relief. “You mean there’s logic to it? It just looked like a collection of arbitrary rules.”
I don’t know about what happens in the Chassidishe community, since I’m half Yekke and half Litvak. Maybe some groups are less demanding.