This is largely a duplicate of other answers and comments, but I thought it would add a bit of background.
You really have two questions:
- What can I do about wrongly failing this review audit?
- Why is this tone acceptable?
Your first question could be clearer: you don't say what action you took to fail, which would help. OTOH, as this question from meta.SE shows, the review audit process for positive answers (i.e. answers where you're supposed to conclude that the "correct" action is to do nothing) is fundamentally broken:
Clicking "Add comment" fails review audit
When the audit system shows you an answer that you're supposed to say is ok, if you do anything to improve it you'll fail the audit... That's totally screwed up.
The only thing you can do about a screwed up review audit system is to bring it up on meta.SE. If you choose to do that, don't focus on the issue of the tone of the answer, and provide more details (e.g. exactly what did you do in the review?).
As to your other question:
- Why is this tone acceptable?
I don't anything wrong with it... yes, it's judgmental, but given the extreme difference between what the OP's exchange team said and what the actual service description reads, I'd say that "unqualified" or "lying" are probably valid judgments. And I don't think that adding a couple mild adjectives makes the judgment aggressive.