Internal audits still have value as it means that someone can't steakily steal money from the reserves without them noticing.
Further, they paid $41 million to settle a case over their lies - https://fortune.com/2021/10/15/tether-crypto-stablecoin-fine...
I don't think it's a stretch at this point to say they have a history of, at the very least, being highly economical with the truth and misrepresenting their own level of transparency. And I do think your argument is unreasonable.
Take a look back to 2017 on the wayback machine -
"Every tether is always backed 1-to-1, by traditional currency held in our reserves. So 1 USD₮ is always equivalent to 1 USD."
"Our reserve holdings are published daily and subject to frequent professional audits."
We know that neither of those things was true.
I would consider this every bit as bad. “We marked our own homework! And guess what? It was great!”
The whole concept is ludicrous.