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
Ralph, I respectfully disagree.

Well over 2 decades ago I learned 2 things (that were only accessible at a reasonable price from PS Audio), things that should be universal if a product is to be called ’High END" 

* differentially balanced AND
* either the preamp or dac has remote Polarity control

Individual songs on discs have long been mastered in various facilities, moreso on Greatest Hits, but still. Most of the time "I" have no problem hearing when polarity is in/out. Over the years I find bass is the greatest offender. When it’s out the music lacks clarity, space is more homogeneous, loses the speed of the initial attack
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Over the years I find bass is the greatest offender.
I hear it more in the brass instruments.