There are many religious practices that are reactionary, medieval and barbaric. Opposition to them is not racist.
The same is true with the Jewish community. Although there is no doubt that most Jews in Britain are more liberal than the Jewish leaders and the Board of Deputies, there is no doubt that the majority are supporters of Zionism. It is also arguable that a majority of Jews do not realize the extent of Israeli racism and how Zionism mandates a form of apartheid.
However it is a fact that a Jewish ethno-nationalist state in Israel cannot be other than a racist apartheid state. The argument that it is anti-Semitic to oppose an identity that is itself based on support for racism is untenable.
If indeed the majority of Jews do support a Zionism that mandates the demolition of Palestinian villages such as Umm al-Hiran in order to build Jewish towns in their place, then that is clearly a racist identity. If the majority of British Jews support a state where the chief rabbi of Safed issues an edict that non-Jews cannot rent property from Jews, then how is that not racist?
The idea that opposition to religious identity is, in itself, a form of racism is a type of blackmail.