It's interesting, but the entire point of the story about the steadying the ark is all about divine authority and following divine procedure. There were proscribed ways of moving with and carrying the ark just as there are for appointing and ordaining elders. The Israelites had grown careless in these procedures and had not followed the Lord's commandments. The ark, like most everything else in Hebrew worship, was symbolic and represented the bond, or connection, between Heaven and Earth. That it was covered with a veil represented the veil that existed between the two abodes. And while it was covered, no man could touch it -- not even the high priest. Uzzah was no priest and he should have known to just let the ark go, for there was nothing forbidding the ark from touching the ground.
Now pertaining to the appointment of elders, it's a fair question to ask how, according to the dictates of scripture, they are chosen and how they receive their authority from On High. We know the rules regarding the ark because it was given by God and carefully recorded. But Uzzah's sin wasn't against the priests and rulers of the people, it was against God, so I don't understand your CO's point. There is no connection or correlation between Heaven and the elders of the Jehovah's Witnesses that I know of. The dos and don'ts of the ark are well documented by the Lord himself; however, the same cannot be said about the qualifications of a JW elder.
So what was his beef? Probably that you were questioning your leaders who have been called and instructed by Jehovah like Moses. Only what leaders would those be?? None of the current or past JW leaders, as far as I know, have heard even a word from God. Even in 1919 God never spoke to the presiding body to announce His momentous decision to choose them as His spokesmen forever, based on his inspection of the world's religions and their leaders.