Why do some manufacturers reverse preamp polarity in the first place?


My Rogue RP-5 reverses polarity, so I switch the pos / neg at speaker terminals. The manual does not mention this, however, I wrote the company and they the amp does reverse the polarity. 

Now my question is...why? I would say 98% of buyers of this amp do not know to reverse the cable connections. I would say most reviewers did not as well. Yes, I realize, polarity reversal is not noticable in most instances. Especially, since many recordings are all over the place when it comes to polarity (at least that is what I've read).

So the question remains...why...why not just have the amp terminals set up so the buyer can just plug in as normal?
aberyclark
Celander, I didn’t know you had a dog in this fight. Be that as it may I see you don’t have any evidence, either. Oh, well, I didn’t really expect any. No biggie. So, what is it, 50% or 92%, hot shot? Guess we’ll never know. 
Geoff, -1 for claiming one has to have a dog in the fight to comment about the obvious. Since when did you ever have “a dog in the fight” to justify the vast majority of your 14,000+ posts?
And I reread them just before making my last post, as most were a quick read without substance. 
The ones without substance are so people like you won’t strain your brain.