Earlier quoted context omitted.
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…
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.