They talking about their enforcement in a pedestrian area. Remember, it's illegal to ride a bike in such an area. They seem to be quite kind if they let people ride bikes until ordered to dismount.
I was riding my bike in Southend pedestrian zone at walking speed in the middle. I thought it would be easier and safer than pushing it, but a policemen came running to me shouting for me to get off and walk. I could understand if if there were people around but the place was deserted. There are signs up saying that cyclists should dismount, but I thought nobody would care if they saw that I was going very slow and there was nobody about but I was wrong. I explained to the policeman that there was more chance of hitting a pedestrian when pushing the bike than riding it, which I could see that he agreed with; however, he was enforcing the rules.
I experienced similar "over enthusiastic" policing when I was riding at walking pace though a shopping street in North Shields (nr Sunderland).
It was just before 4pm on a cold, damp, dark Sunday in February with less than 10 pedestrians in the whole town.
I visited the police station afterwards to explain why - in my view - there was no need for the officers to stop me.
The desk sergeant confirmed to offices could have given me a ticket, and that I should be grateful that they had decided to offer advice instead.
Meanwhile I regularly see folk on bikes (delivery types on E-bikes, kids on E-scooters, yooths cycling furiously though the crowds in summer who are not stopped.
It's on my personal top-5 list of "Worst experiences I had when dealing with the Police"