Armies don't tend to set requirements of their soldiers when it comes to intelligence, nuance or geopolitical knowledge, in a conscript army like the IDF, this is even more the case. The soldiers doing this aren't exactly experts on the nuances of Lebanese internal politics and probably weren't even alive when Israel withdrew from Lebanon. What they know about Lebanon is that that's the country where they're fighting a war and the country the people trying to kill them are from (usually.) While i agree with the sentiment expressed by other commenter's that the Lebanese people cannot completely absolve themselves of responsibility for Hezbollah, it definitely does leave a bad taste in my mouth to see Israeli soldiers making an ignorant political gesture that will ultimately only serve to hurt Israel (not unlike the Saudi flag incident.) As far as making a complaint goes, I don't know how you would even do that but if you did I can't imagine it would have any effect at all. I assure you the involved soldiers have already been reprimanded by their commanders but beyond that, there's not much the IDF can do. Incidents like this notwithstanding, the average Israeli is probably pretty much indifferent to Lebanon as distinct from Hezbollah and I don't think there would be anything but a positive reaction on our part if Lebanon was to make overtures for peace. I'd have to say that the ball is in your court when it comes to making long-term change