The true lesson of Kamtza and Bar Kamtza, and the destruction of Jerusalem and the Temple, is that consequences must be considered. If God was the ultimate author of the calamities of 70 C.E., then it was God Himself who rejected following a strict interpretation of halachah in the face of impending disaster. It was He who punished His people for not allowing a more liberal interpretation of the law to hold sway long enough to avert disaster.
Sometimes, God was saying, religious authorities must set aside their aversion to compromise. When the fate of the People Israel is at stake, they must be more accepting of other views and must be more honest in admitting that their views may not be the only ones that will please God. They can hold to their views, but they must neither demonize nor delegitimate those who think differently.