From page 2 of the 3310 review:
"The power amplifier section is rated at 120 watts RMS x 7 into 8 ohms, and 160 watts RMS into 6 ohms. This means it is not rated into 4 ohms, and you will see in the Bench Test section why this is so."
And from page 3:
"I tested the 3310 with various bookshelf speakers that I have on hand, and again, I want to make it clear that you should only use 8 ohm speakers with this receiver."
And again from page 3:
"I used 8 ohm speakers, but they are not very efficient, so I had to crank the volume control to get the SPL I wanted, and there is a bit of brightness in the sound when it's cranked like this. The bench tests will show you why this occurs. So, not only should you use 8 ohm speakers with this receiver, you will need high efficiency as well (> 90 dB/w/m)."
From page 4:
"THD+N vs. Frequency shows why you should use 8 ohm speaker with this receiver. Even the 8 ohm load resulted in distortion at 0.2% near the upper limit of hearing. Using 4 ohm load caused the receiver to go into fault above 1 kHz.
Note that the 8 ohm measurements are using 50 watts output, which is above the average listening level." [Emphasis added throughout.]
"The THD+N vs. Power Output measurement indicated that the 3310, with two channels driven, will deliver 140 watts per channel RMS at the knee, then rises rapidly to clip (1% THD+N) at 160 watts. The 4 ohm measurement is only for comparison and interest. Don't be trying to drive your old 4 ohm speakers to high volume with this receiver.
In the comments section Mr. Johnson stated the following:
"20 Volts into 8 ohms is 50 watts. 20 volts into 4 ohms is 100 watts.
The formula is voltage squared divided by the impedance. I tested it into 4 ohms just to see the limits of its performance and to maintain consistency with previous reviews. Even using a high pass setting in the bass management of the receiver at about 80 Hz might still compromise the receiver with a 4 ohm speaker, because some 4 ohm speakers dip down to low impedance at high frequencies."
From this I am inferring that the 3310 was beyond its abilities at 100 watts into a 4 Ohm load. "Using 4 ohm load caused the receiver to go into fault above 1 kHz."
I think this is an honest interpretation of his words.
And whether an AVR is a luxury good or not, most of the world still wants honest value for their dollars. Maybe you don't. This would seem odd as you are obviously a community minded man, considering all your free work on behalf of Denon owners. I think this is commendable and thus find your somewhat ultra-capitalist statement rather puzzling.