Looking at the article, the pcso does pass as a man. Unless they’ve changed their appearance, then I would be suspicious that the shouter knew their past, and that it was a targeted shout rather than a questioning one.
PCSO Freel has been open about being transgender. Its likely that many people in Mold have heard Freel speak about this as part of Hate Crime campaigns:
BBC Wales 'Transgender officer Connor Freel shares experiences to help others'
17 October 2018
(extract)
"Now a police community support officer (PCSO) based in Mold, Flintshire, he is backing North Wales Police's campaign during Hate Crimes Awareness Week.
"It's great if my experience can help others," he said. "That drives me on."
Conor was born female but, from an early age, he said he felt he had been born in the "wrong body".
"I told my parents when I was a small child that I was a boy," he said.
"When I was around 15 I changed my name to Connor and felt free.
"I was no longer acting and not trying to fit into some sort of box I didn't belong in." (continues)
concludes
"Everyone has been great and I don't have any issues with the public. I have now got a male body shape and no-one suspects I was born female."
Connor's story is part of a campaign by the police to raise awareness of a 27% increase in hate crime across north Wales in the last 12 months.
The number of cases rose from 358 to 455, with incidents involving race and religion featuring prominently.
North Wales Police and Crime Commissioner Arfon Jones urged people to "speak out and not to suffer in silence".
Help charity Victim Support said such abuse was "ruining lives", leading to mental health problems and social isolation."
www.bbc.com/news/uk-wales-45890976