All of the arguments made against the Gospels involve making large assumptions. In order for the arguments to be valid, assumptions have to be made about the Jewish authorities and their motivations and behavior. For instance, the assumption has to be made that they were honest and not corrupt, that they would never break any Jewish law or distort any Jewish law in order to make it possible to do what they wanted to do.

We know from recent experience that authority figures who are corrupt do indeed break and distort their own laws in order to do whatever they want to do. It's against the law for the US government to hold prisoners indefinitely without charges, and to torture people. This didn't stop them from doing these things, however.

The charge against the Jewish authorities (and not "the Jewish people"), is that they were corrupt. So in the context of the New Testament, it would make sense for them to break Jewish law in order to accomplish what they wanted to do.