The oil from the factory is no different than what is used when they change it. There was a time when a different break in oil was the case. Those times went away with most Amal carbs.
For a tech to make the statement that they see all kinds of stuff come out means that the tech should be fired. Really? A bunch of crap? Uhhh, filter 101 fella! If all that "crap" is floating around, as he says, then you have bigger problems than changing your oil too soon and you need to file a warranty claim for a new motor as something must have broken.
There is no benefit to changing your oil any sooner than the recommended intervals. If you doubt this, have it analyzed by an oil evaluation company. You are wasting your time and, most importantly, your money.
But, hey, like I said, it's been a while since we had a ridiculous oil thread around here.