Why did the romans allow the Jews to still worship their religion after they were captured?

The Roman Empire did not generally force cultural changes on conquered territories until after Christianity was adopted as the official religion. As long as they were getting taxes and the populace was not revolting, they were satisfied with letting them be as they were for the most part. During this time, only when religious revolts were happening or on the verge did they outlaw the practices of various religions.

Once they adopted Christianity as the official religion, the Roman Empire became very anti semitic and intolerant of anything that did not follow the official creed. During this time there were many things done in the name of Jesus that were in direct opposition to the teachings of Jesus.