Fair enough just an odd conclusion to take. If a headphone has -10dB tuning in bass region, that could be a reason not to buy that headphone outright. If a simple EQ to that frequency reduces this issue then why is that dishonest to mention? Some headphones you simply cannot EQ as it distorts.

Similar to if you have 2 headphones, with one being much harder to drive you wouldn't review both from the same low power source, you would appreciate the different requirements of each headphone and review accordingly.

People buying an open backed low sensitivity headphone that requires an amp to drive properly would know what EQ is I think. If this was a review on Apple air pods then fair enough, maybe they wouldn't.

The point of consumers reading reviews is to help them make an informed decision. If applying EQ to a headphone improves enjoyment or lessens some of the drawbacks of stock tuning it is fair for this to be mentioned in reviews. I didn't say that the review should only mention sound when EQ'd. If it doesn't improve enjoyment then that also is fair to say. Nothing dishonest about that IMO.

"Closing the gap in performance" - sounds like a positive thing for me, especially if it is free to do so.

I think most informed people that buy the HE400SE will be EQ'ing it, so odd to review it just with stock tuning.

You mentioned that you don't value soundstage width on headphones but then say you don't EQ as it reduces this ?

I got both HD560s and HE600s with me currently A/B using LS50 speakers + sub as a reference and HE400SE once EQ'd does not sound broken to me it actually sounds very good.

Did you even try them both with oratory EQ? HD560s stock tuning is decent ish so not that much of a change. HE400SE benefits a lot.