oh - you mean that trade where you perform other folks creations for money, but pay no royalties to whoever wrote the tune
there's no point debating ethics with musicians
PS
quote "The trade, above all others, where amateurs constantly clamour to do your job for free. and are convinced they are "just as good" -end quote
As a musician myself, I have so say that
some of the folks now performing for free on you tube, are better than 99% of pros. Listen to Sungha Jung. Betcha can't play that, as the folks at Guitar World like to say.