Interesting to see that slope, although as you say they were likely airborne thereabouts so it may not have had much input into what happened.
I should say that this particular horse, while rated, is low time on the C-47, so I'd certainly bow to greater experience! However I have studied the DC3/C-47 in some depth and am reminded of an incident a year or so earlier in which one lost 14ft of its port wing and was able to be flown successfully to a landing. Thus, although there could well be other mechanical reasons why control was ultimately lost, in this case I'm disinclined to take the view that a few feet of bent wingtip would be sufficient in itself.
That said they are known for a somewhat nasty wingdrop on stall when under power, and while that is usually portside the bent wingtip and other factors may have altered that characteristic, particularly once they'd got out of ground effect. I mention this because the last sentence or two of the report suggests the pilots (while in ground effect) may have thought they could control the machine and chose to fly it, rather than close the throttles and stop. With just a few hundred feet of runway remaining such a decision seems reasonable, but once fully airborne they could well have found the situation somewhat different - especially if there were control issues, either due to some rigging problem or as a result of the wing damage.
FYI here's a photograph of NZ3501, 21st March 1945, showing the damage it sustained as a result of collision, yet was still flyable. The photograph appears in
DC3 Southern Skies Pioneer by Brian Lockstone and Paul Harrison (ISBN 1 86941 390 3) but this image is cropped and lightly enhanced from
www.airhistory.net:
FP.