My comment was multi faceted, including the fact that Rav Moshe held very strongly that people should rely on hechsherim, and the bashing of a hechsher by a competent rav is not something he would condone.
I asked the posek in YSI who is a very close talmid and he said I don't need to be makpid on DE. To be clear, this was his psak, I didn't ask what Rav Moshe held.
My intention was not to bash anyone. The owner of rita insinuated in his letter that the rav hamachshir is an experienced pioneer of kashrush in lakewood and that is not the case.
Bottom line is they are relying on kulos many would not want to rely on. The fact that your rov said DE is okay is irrelevant. You can follow your rov and great, but many people don't want to eat DE nor do they want to eat in an establishment that has cholov stam relying on a non jew to make sure that they don't get mixed up. To add to all this they are not forthright about this at all, there is no sign in the store that states what is being served and what kulos are being relied on.
That being said I still stand by what I said IMHO a ben torah should not be patronizing that establishmment as is not up to the standards many bnei torah are keeping. It's not like anyone will starve if they ch"v don't eat rita's.
As far as what R' Moshe would say are you an expert on his opinion? Are you a talmid? Are you familiar with all his teshuvos and psokim?