In revolutionary Ireland Protestants were overwhelmingly unionist and anti-Home Rule

It is quite often said that many protestants filled the republican ranks in revolutionary Ireland. This is true to a degree. There are examples of protestant republicans, however these oft-recounted individuals were outliers. The overwhelming majority of protestants were unionist and anti-Home Rule. Ronald McNeill wrote in 1922, 'Ulster's Stand For the Union':

"An additional cause of offence, moreover, was that he was at that time trying to persuade credulous people in England that there was in Ulster a party of Liberals and Protestant Home Rulers, of which he [Lord Pirrie] posed as leader, although everyone on the spot knew that the “party” would not fill a tramcar."

Ireland's Revolutionary and Fairyhouse traditions

Irish Grand National (1921) - Won by Mr A. Wills’ ‘Bohernore’ at Fairyhouse. 

Stephen Gwynn wrote an account of Dublin during the Easter Rising of April 1916:

"On Monday a very large proportion of the officers from the Curragh and the Dublin garrison were at the Fairyhouse races. In the Castle itself there was only the ordinary guard."