https://www.legislation.gov.uk/asp/2021/14/section/3/enacted
https://www.legislation.gov.uk/asp/2021/14/section/4/enacted
https://www.legislation.gov.uk/asp/2021/14/section/3/enacted
https://www.legislation.gov.uk/asp/2021/14/section/4/enacted
Of course, that's still highly problematic. Is a statement like "Marjorie Taylor Greene wants to replace secular democracy with a theocracy based on a twisted interpretation of Christianity" likely to stir up hatred against fundamentalist Christians? It's ambiguous enough to have a chilling effect.
Also "Christian fundamentalist" isn't a protected class. If anything they're the class many protected classes need protecting from.
Religion is a named protected class in the legislation. There is no reason to believe it couldn't be applied to extreme or fundamentalist religions, and I chose a particularly contemptible example of it to illustrate a point.