Judas may or may not have been part of the group identified as the Zealots, but the Zealots were certainly not supporters of Jesus in general. They were a semi-fanatical Jewish group already in existence long before the rise of Jesus and his followers.Jesus was also by no means apolitical. In fact multiple accounts depict him as claiming exactly that he was the messiah via his terms "Son of Man" and "Son of God", which is in the end the reason he was handed over to the Romans and crucified. The people who heard these words, including his disciples, the common people, and more importantly the Sanhedrin, knew exactly what he meant when he used those terms, and that is why they basically flipped their lids and wanted to have him killed. The Messiah was not just a theological idea for the Jews of the time, it was very much also a political term, because it meant to them that he was stating that he wanted to overthrow/conquer the Romans. This would obviously endanger their privileged status within the current order and bring the wrath of the Romans upon them. So they framed him as a revolutionary trouble-maker and Pilate eventually agreed to kill him.
Also, the Old Testament depicts God handing the Promised Land to the Israelites via military conquest (as a judgment against the conquered peoples), but even in the Old Testament there is no general mandate for Israel to destroy other nations militarily as a routine part of practicing the religion. And neither does the New Testament contain such a mandate.
