I agree with Meno. Don’t daven there.
I think you can speak to the rav, but go into the conversation with an open mind about his reasoning, and understand that he may not be able to share it with you.
If this minyan were a youth minyan for at risk kids, we would all look at this very differently. Well, maybe the rav looks at it as a minyan for at risk adults.
If you think about it, for the most part, someone makpid on davening wouldn’t daven there (I’m sure DaMoshe’s father does care about davening, which is why I said “for the most part”).
So who’s attracted to such a shul? People who are lax in at least one area of avodas Hashem, and likely in more. If every shul would not tolerate the talkers, the talkers would not have a shul to go to. The rav’s cheshbon might be that they’re better off in his shul talking, where he can perhaps have a positive influence on them in other areas, than on the streets, or forming their own minyan with no guidance whatsoever.