Ujm, happens to be I’ve heard the story about rav avrohom yehoshua criticizing, or in the brisker lingo, levying “bikores” on rav Moshe. He had no problem doing so publicly in his 30s when ue came out shtark against rav shach, the gadol hador. It’s not that he didn’t hold of them, it’s a brisker mahalach which is commonly misunderstood. And I’ve heard the part about a bochur saying “in America we say that a soloveitchik made a churban”
But…it also got brisker talmidim blacklisted in the rest of the israeli yeshiva world. Not so in America; quite the opposite, actually.
As for a rebbe publicly calling rav avrohom yehoshua by his English initials…does he call rabbi yoshe ber JB? Probably not. It’s an insult to kovod Hatorah. Whatever you think of rav avrohom yehoshua, he was respected by the brisker inner circles, despite there being plenty of politics. Darchei is a great Yeshiva, but that’s not something a talmid chacham would do – if for nothing else than for the position rav avrohom yehoshua occupies. It’s a bizayon Hatorah.