A lot of good responses on this thread.
I personally don’t believe Joseph is a kiruv rabbi.
Let’s say a Jewish man wants to become frum but is married to a secular Jewish woman? Should we urge him to immediately leave her? After all, every moment she is refusing to immediately become 100% frum she is causing him to sin in various ways! Of course not. Some misguided kiruv rabbis might do this, but not the reasonable ones. Rav Arush’s Garden of Peace has an important discussion of such issues.
It’s a similar issue when a goy wants to convert but is already married to a Jew. We don’t urge him to immediately leave the Jew (although that would put an end to some aveiros), because if he plays his cards right she may well become a BT and everyone will be better off. Both these last two are common scenarios.