>>> How does that make any difference?
Because, under the provisions of Section 66 of the Sentencing Act 2020, 'religious hostility' is an aggravating factor in an offence, which can push sentencing upwards:
https://www.legislation.gov.uk/ukpga/2020/17/section/66/enacted
Therefore, when a defendant has pleaded guilty to an offence, or been found guilty of it by a jury, but denies the prosecution's assertion that religious hostility was involved in it, it's necessary for a Newton hearing to be held before sentencing can take place:
https://en.wikipedia.org/wiki/Newton_hearing