It wasn't (just) 'arrogant', it included a complete disregard for facts, rules, procedures, and other members.
It's the same attitude that many have throughout government (and media) with regard to investigating election fraud and/or the China Flu.
And it's more than 'condescending', it's a word that means 'stare straight ahead and damn the facts - I've got an agenda'. It's a word that signifies 'I am in power, and I am ignoring you'.
What is the proper word?
Cockwomble – A person, usually male or female, prone to making outrageously stupid statements and/or inappropriate behavior while generally having a very high opinion of his own wisdom and importance. Yes, I learned this word on GA.win