[nomadking]

They have been charged under public order laws with using ‘threatening, abusive or insulting words’ that were ‘religiously aggravated’.

...
Although the facts are disputed, it is thought that during the conversation the couple were challenged over their Christian beliefs.

Ben and Sharon Vogelenzang are charged with breaching Section 5 of the Public Order Act – causing harassment, alarm or distress. If convicted, they face fines of £2,500 each and a criminal record.
The Muslim woman was staying at the Bounty House Hotel in Liverpool, which is run by the Vogelenzangs, when a conversation arose between the hoteliers and their guest about her faith.


It is understood that among the topics debated was whether Jesus was a minor prophet, as Islam teaches, or whether he was the Son of God, as Christianity teaches.
Among the things Mr Vogelenzang, 53, is alleged to have said is that Mohammad was a warlord. His wife, 54, is said to have stated that Muslim dress is a form of bondage for women.
The conversation, on March 20, was reported by the woman to Merseyside Police. Officers told the couple that they wanted to interview them over the incident.
After being questioned on April 20, they were interrogated again three months later before being charged on July 29 with a religiously-aggravated public order offence. They appeared in court on August 14 and are now awaiting trial.

So it seems possible that they weren't even the ones to bring up religion in the first place. So it may be, that they were the ones that had their religion insulted first, but as as they are not fascists they didn't complain to the Police.