If only it were that easy. I don't think that the problem will go away simply if we are more brutal and cruel to the enemy. If this is so why are they still bothering us? According to your understanding of the Crusades they should have disappeared centuries ago.
I think there is something more to it than just how vicious we are.
The problem is that aside from a few long-gone phases in the Joshua era, Jews have never come close to treating their enemies as they deserve. Time and time again we see, both in Scripture and observable human history, the Israelite nation sparing various Amalek entities for one stupid reason or another. The problem has never been worse than today, when around half of secular, brainwashed Israelis--and the vast majority of left-wing, assimilated, Hellenized Jews around the world--believe in "human rights" for their Nazi enemies. Chaim Ben Pesach illustrates this when he says that most Jews today "don't have the stomach" to treat Amalek as the Bible commands.
The Shoah took place in large part for this very reason. Read Anne Frank. The vast majority of Jews could not fathom violent armed resistance to the German Nazis even during the peak of the death camps. In the few times when a few Jews actually did decide to fight fire with fire during the Shoah (i.e. the Warsaw Ghetto), the result was nothing short of astonishing considering how severely outnumbered and outgunned the Jewish freedom fighters were. Some of the nations in the Nazi empire, such as Poland and Hungary, had enormous Jewish populations (10 or 15%), and with the higher Jewish birthrate, a huge amount of those Jews would have been of prime young military age. If Jews as a whole had gotten together and decided that they would go underground, take up arms, and resist the Nazis with everything they had, it would have been nearly impossble for the Germans to even stand still in those countries, let alone march on to Russia and throw the Jews into gas chambers.
Your comments about Shoa are very naive. You mix half truths. You should read about how Holocaust actually happened - the Germans never openly murdered Jews without actually giving them a hope, a sense of normalcy, of order. There was a whole method of ostracizing Jews among native population, of reducing them to animal-like behavior, to creating false hopes, to create new behavior of a defeated person without any rights. The nazi murder machine was very devious and complex. And Germans didn't gas 6mln Jews - a great deal of Jews were starved, shot, fell to illness, froze, etc. And a great number of Jews died in the battle. Only in Red Army, more than 250,000 Jews were killed (out of more than 600,000 enlisted), not murdered. There were many Jewish partisans in France and Poland.
This sheep or slave-like behaviour is not typical of Jews only. Look at Soviet POW - more than 50%, or 3 mln of them, were murdered in nazi concentration camps - and these were soldiers, able bodied men! Yet, nazi murder machine, through executions, hunger, torture, etc, has reduced them to a level were cannibalism thrived, were they felt and behaved like slaves. What did you expect Jewish women, children, grandparents to do - to revolt?! You know, that for one Jew escaping a ghetto to Partisans, Germans SS Police would murder hundreds of Jews in the ghetto? Is it easy to make such a decision? Can one leave a grand parents and children behind, knowing that they'll be murdered, along with hundred of other Jews? And were are you going to run? To population that hate your guts and that would report you back to nazis? I am not saying that some elements of "sheep" mentality didn't play their part - they unquestionably did, but please don't oversimplify the matter. What is maddening and is even more telling now is that Israeli, being the local superpower, still have all the elements of this galut ghetto mentality. And swine like Savage who accuses Jews of being hapless victims of nazis - like sheep to the slaughter, now states that a two state solution is inevitable (read Auschwitz borders) and we should just get alone.