Here's my two (rapidly devaluing US$) cents worth.
If you don't maneuver in the vertical (that is, climb or descend), then what is said may be true. Once you start to maneuver in the vertical, (i.e. climb or descend), then things become a bit different.
Now you have to look at your total energy with respect to the earth, and groundspeed becomes important.
My experience is that if your airspeed is less than 4 times the windspeed (and this is only a rough guess), then the effect of wind is quite pronounced when you maneuver in the vertical.
The folks who see this most are model airplane fliers, and then ultralight pilots. Both operate at very low airspeeds, and any wind effects them dramatically. I've watched Cessna 150s depart from Mojave with a 35 knot wind and when they turn crosswind, they simply stop climbing. I've also had a Dash-8 crew tell me their experience when climbing into a 100 knot headwind at altitude. When ATC gave them a turn out the headwind, they said they literally fell out of the sky.
One last story- when the F-15 Streak Eagle set the altitude record, they did a wifferdill (specific maneuver to get to best climb speed at altitude) to go downwind with a 100 knot jet stream before they started their climb - this gave them more kinetic energy with respect to the earth.
So something gives. Somewhere there is a physicist who could put this to bed nicely. Anyone looked at See How it Flies for more discussion?