Uhh...
1) No, I never played D&D in any form. Stayed away from it, mainly due to my Messianic Jewish/Christian/whatever-you-want-to-call-it upbringing.
2) While I can't speak for elite units, standard combat soldier training in the IDF is all about discipline - during basic. Follow orders, know the procedures, be comitted to the service. In advanced training (which immediately follows basic training, natch), the discipline aspect is greatly dropped (you start to call your sergents and immediate officers by first name instead of rank; incidentally, in the public school system it's the same, where you call teachers by first name, not "Mr./Mrs. McCready"). Instead, advanced training focuses on personal excellence in combat, first the personal-level training maneuvers, then squad-level (3 ppl), unit-level (11 ppl), company-level (~35 ppl), etc. You also learn whatever non-generic stuff you need for your position, both on the personal level (AT, mortar, HMG, sharpshooter) as well as the larger scale (combat engineers learn about explosives, mines & minefields, AT obstacles, etc).
The only "desensitization" a standard combat soldier goes through with regard to killing people, Kal, is having human-shaped cardboard cutout targets on the firing range - hardly effective I would think.
Back on topic, however, I can see how they would get such an impression from D&D players. The few I've known have seemed to be obsessed with the game to the point where nearly everything they encounter and say is filtered through "D&D-colored" glasses.