The important fact is that no two drops are the same and it’s probably not “one” technique, but a lot of different ones, which you needt to be able to apply to suit the drop your are, er, dropping!
So to say “don’t manual off” or “don’t pop” is really eronious, because it the drop is tight, tall and you can’t drop off at any speed, then you are going to HAVE to manual off it!
In extremis, we have the trials style drop from a rear wheel stand, where the drop is left at zero speed, ie from a continuously held “manual” and is started with a pedal hop off. At the other end are those bike park drops, with 100 yards of straigth run in, 100 yards of straight run out, with the landing at just the right angle, in just the right place and a perfect take off ramp, smooth, flat, no lips, easy to judge, and sure, you can ride right off those at 100 mph without doing anything and it’ll all be good.
The real world is probably somewhere in the middle….. 🙂
Which is why you need to get out a ride all sorts of drops, and not just practise the one you happen to have in your local bike park