He once was [on the Vaad’s kashrus committee], and left.
Yes, because he was accused of having a conflict of interest since he had a private hashgocha in a different community. Somehow, the rabbi who worked for the OU was not accused of having a conflict of interest (I actually think it makes sense to have rabbonim on the kashrus committee who are involved in hashgocha because they are bigger experts).
a businessman who may be a kosher, ehrliche Yid, is put out of business.
That’s factually incorrect. The majority of establishments in the FT are not on “the list”, yet are still open.
If a hechsher is reliable, it should be enough
That’s fine for those who consider those standards acceptable, and nobody’s trying to close down any establishments which are under the Vaad, but what about the people living in the FT/FR whose standards are different? Do you really have a problem if they have a pizza shop, fleishig restaurant, or take-out place which they are comfortable with? Must they travel to Brooklyn to get the meat or chicken with the shechitah they prefer?
no one should be allowed to be motzi shem ra on it.
We agree on that. Thankfully, nobody is being motzi shem ra on the Vaad.