Well, I actually had read it as he was engaging it with the rpm's up to speed (which was the case). When I had a manual double clutch tractor, it was not the problem as you could feather in the PTO. Now with my my HST/electric PTO, it is not a pleasant sound or feeling if I engage with the engine wound up too much.
On a side note, I had about 10 acres of overgrowth on my property when I purchased the place and went through a bunch of shear bolts. Now that it is cleared, I haven't had one break on almost a year of use.