A bit of entertainment in the middle of a dull work week ;-) ?
The responses fall into 3 main categories:

1.
Anecdotal evidence or pseudo-technical speculations:
"...I [, my wife etc...] notice that GP is really easier on our bodies..."
It is not your tendons that are aching due to wear, or bones grinding due to excessive strokes.
Your *muscles* are less sore with GP because you probably don't have the fitness/power to operate larger blade.
Have you been using the large blade regularly, you might observe no such phenomenon. GP may serve your specific instance better but no general conclusions should be drawn.

Here is what is really needed: skilled paddler, equally adept at GP and Euro blade to paddle a sprint, middle distance, long distance....
Measure: boat speed, stroke rate, VO2 uptake, HR (heart rate), energy expenditure etc.
Only then you can draw any conclusion which paddle is "more efficient", "easier" etc.
You can substitute the single paddler for a sample large and diversified enough to be statistically meaningful.

2.
The Original Post did not follow the Nickelodeon ".. I love you, you love me..." melody, so there was a fair amount of plain hate mail.
Since the OP a) did not insult any specific person nor b) even a group of people, only questioned the method of reasoning, this attitude is disappointing.

3.
Small group who "groked" the true intent:
"...Tommy was getting at the so-called, conventional wisdom of the paddling community..."
"...did a good job provoking the mob to think..."
http://www.kayakforum.com/cgi-bin/Building/index.cgi/noframes/read/165722

If the trifle matter of this post stirred the emotions so much, wait till you see Part 2 on a completely different yet 100% kayak - related issue.