David Moffatt, 39, made the remarks after entering a shop in Cricklewood Broadway, Brent, north London, on May 23.
Police were called at around 2.45pm and witnesses told officers the suspect was wearing an orange high-visibility jacket and trousers.
Moffatt, of Ivy Road, Brent, north London, was identified and arrested at 11.30pm after calling police to claim he had been threatened.
When the allegation was put to him, he said: "I'm not anti-Muslim, I'm Catholic."
Moffatt pleaded guilty to religiously aggravated harassment at Willesden Magistrates' Court on July 28, the Metropolitan Police said.
He was sentenced to 100 hours of unpaid work and ordered to pay £620 in costs and a victim surcharge of £85.
Detective Inspector Madeline Ryder said: "Hate crime is unacceptable and Brent's community safety unit is committed to tackling hate crime in all its forms, supporting victims and their families and bringing perpetrators like Moffatt to justice."
