Your slightly cryptic post intrigued me so I clicked a few times and found this interesting story.
https://www.city-journal.org/html/how-dagger-john-saved-new-york%E2%80%99s-irish-11934.html
Part of the way through the article quotes George T. Strong (as an example of anti-Irish bigotry) and refers to him as “former mayor.” I must have missed that part of his career.
Wikipedia does not mention Strong’s being mayor. Perhaps the City Journal’s writer got him mixed up with someone else.
Although George T. is quite negative about the Irish, I would say he had an “anti-Irish attitude,” rather than “bigotry” or “prejudice.” Many of the Irish pouring into New York at the time were at quite a low level of sanitation, culture, and education. They also had a high crime rate, as poor, immigrant, uneducated, young men often do. His views, therefore, while not kind, were based on experience.