If you look at my earlier post I found that when hand chambering a round following the slide forward and depressing the back of the extractor as it is about to contact the case rim prevents the extractor from making any contact, thus not causing any potential damage to the extractor. My carry guns usually stays loaded for 2 weeks at a time so it's really not that much of a hassle considering i'm only doing it a couple times a month.
I know of no manufacturer that recommends loading their pistol in this way.
The Beretta 92 was designed so you could manually load a round in the event of a magazine failure. It's one of the reasons it was picked as our military's sidearm.