Well, I don't know about defining them as the slacker class (many are overworked business types), but I would say that a significant number of them were also of the slacker type. However, especially during the end of the war, when they called up thousands of miluiimnikim (reserves soldiers), the fact that many of them were totally physically and psychologically unprepared for battle was very true.
For the regular army combat soldiers who are in their mandatory service (18-22), they are immersed in the military and quasi-combat situations on a daily basis (anything from guard duty, working the checkpoints and roadblocks to actual operations). But for the miluiimnikim, most of these people maybe have one month of duty a year (if), including some little training outings where you run around for three days and shoot targets or so. So you had many computer programmers, office workers, family men, suddenly suited up and sent off to open combat within days.
Geographic space is so small here it sometimes surreal. I very often find myself in the Occupied Palestinian Territories and I never get over how surreal it is to go in minutes from West Jerusalem to a city in the West Bank. The second you hit Kvish Ha-Minarot (the settlers' tunnel road) things suddenly change, the ugly Wall, the roadblocks, then a couple minutes later you may as well (and should technically) be in a different country. It is uncanny and I think this psychological dislocation increases by several fold when you have people who were sitting in their office smacking away at a computer a few days ago, and then suddenly are suited up, drive a couple hours north and then are walked over the border into open combat, or even stranger the ones who are called up, get in a transport helicopter and a little while later are under fire and maneuvering away from an anti-aircraft missile (which happened to someone I know).
On the other hand, the southern Lebanese people have been living under a situation of real threat and war for a very long time (Israelis think and feel that they are vaguely under threat from outside and inside enemies, but that is nothing compared to what the S. Lebanese lived under until Barak's pullout from Lebanon in 2000, which everyone but very small children would remember, and even after that the Israeli flyovers and such). Plus the Hizbollah have been in constant preparation and training for just such an occurrence. So, on the whole, they were physically, training-wise and psychologically more prepared for the battles.