ubiq, others have above amply addressed your point about business honesty, but even putting that quote from the MO rabbi aside, how could you possibly say the rabbi was right and advocate that Avira return to the sin-agogue where the “rabbi” presides over a crowded mixed mingling and hand shaking by his constituents during a “kiddush” — and when questioned about this abominable situation tells his teenage mispallel (Avira) that he should be wary of being “extreme” and that he’s “going through a phase”?
The teenager was correct and the rabbi dead wrong; there’s nothing extreme or going through a phase when questioning the wrongfulness of not adhering to shomer negia, tznius and mixed gender socializing during a shul kiddush.