Is it ethical for someone to report 1 or 2 late payments for 7 years? Sure, it's legal, but is it ethical for them to continue to hamper your efforts to improve your life and learn from past mistakes? Only you can decide...no one else.
CRAs have to be able to verify it by the original records to report it and if they can't, then they can't report it. Disputing is the avenue afforded us to request verification. You are simply asking them to check their records to confirm.
IMO, It doesn't matter one bit what we know or don't know. We aren't reporting anything. The law is clear that if the CRA is to report an account, they must be able to verify it with the furnisher (among other things). If the account, lates, etc cannot be verified- off it goes. There is no section of the FCRA that states that a consumer's personal knowledge of an account has any bearing on it's reporting or the CRA's requirement to verify. Doesn't matter.
There is no ethical dilemma about disputing accounts that you personally know are reporting correctly. What you know/don't know isn't relevant. (Try to have a non-reporting positive account put ON your reports for an idea of how little what you know matters).

All you are doing is demanding the CRA prove that they can verify what they are reporting (no more, no less).
Making false statements is another matter, saying "I was never late" when you in fact were isn't appropriate nor is it necessary. Instead of claiming you were never late, insist the CRA prove that the lates that they report are accurate. "Please provide evidence that this information is accurate and belongs on my report" accomplishes the same thing as "I was never late" without making any statements on your part.