If you have a defective razor or blade, than I would agree, technique is not the problem.
Furthermore, if you have bumps, they are going to get cut-off, and one had better tread lightly.
However, when Marc talks about blade angle, etc. that is all part of "technique". I worked on my technique with open-comb razors so that I could judge my angle. If it is not extreme enough, you leave tracks with the open-comb. A safety-bar razor can squeegee the lather off, as opposed to the blade doing this!
Finally, another component of proper “technique” is pressure. This needs to be varied depending on the razor and the blade. When I first joined this Forum, I would read, “...no pressure...” over-and-over; until a 2008 post where Squire referred to the “...pressure necessary...”. The fact is that good technique dictates that the pressure you use is related to the razor (head weight, handle length, balance, etc.), as well as, the blade used (sharpness, hone, etc.), and also the thinkness and slickness of your lather. You don’t use the same pressure (technique) with every razor/blade combination or lather.
My father had a stroke in August of 2010 and I will usually give him a shave once a week on Saturday. Since he also suffered from blood clots in his legs and feet, he is on high doses of blood thinner. What he hates most about shaves is the “pulling”; so I have been using a long handled razor with either an open-comb Merkur or Muhle head, and either a Feather or Super Iridium blade. In over 40 of these shaves, I have yet to draw blood (which is more than I can say about shaving myself.) There is nothing like shaving someone else to perfect your technique. I’m tempted to take the straight razor over to Dad’s one of these weekends and see what he says!