Regardless of how you word it, it amounts to the same thing: the protocol and signed, validated history say this happened, now we act like they did not, which is a violation of blockchain integrity.

No, that's not what happened. No history was changed, and nothing was re-validated as you suggest. There was no "violation of blockchain integrity". The only thing that happened was that the upgraded version executed what's known as an "irregular state-change" which moved the ETH from TheDAO's smart contract to a new secure contract. So, it wasn't a roll-back, but a roll-forward, and the change was mined using PoW in accordance with all the blockchain block selection rules.

The hackers ("hackers") made valid transactions.

The hard fork reversed those transactions.

No matter what fancy spin you put on it, that was absolutely a violation of the blockchain's integrity, as it violated the principle that accepted transactions can't be reversed after the fact, even if you call it an "irregular state-change" that just keeps things secure.

You can absolutely defend the position that this was best for the ETH ecosystem. But it was absolutely a reneging on the blockchain rules.