"They were never going to allow Home Rule to come into being."
To ascertain this, in 1929, having gerrymandered a Protestant majority and declared that the North would be a Protestant State, they abandoned the Proportional Representation system of voting and installed a first past the post system, this way making sure that the Catholics had no say in the running of the State.
Additiuonally, under this system, Catholics were disadvantaged further when it came to the vote because of the property ownership restrictions to elections (see below description)
Jim Carroll

The commonly understood impetus for civil rights grievances is the way unionists dominated government in Northern Ireland after partition in 1921. Under the devolved Stormont regime, anti-Catholic discrimination occurred in private and public employment and public services, particularly those provided by local councils. Although some debate the character of the postpartition state in both politics and scholarship, a broad consensus agrees that, from 1921 to 1968, the devolved political system supported and legitimated widespread discrimination against the Catholic minority (e.g., Darby 1976; Whyte 1983).
State discrimination was most pronounced in local government. Local authorities preferentially allocated public housing to Protestants, and the system for voting in local elections meant housing discrimination had electoral consequences. That is, under Northern Irish voting laws, only "ratepayers"— either property owners or public housing tenants, both of whom paid a local property tax called "rates"—or their nominated representatives could vote in local elections. Private tenants did not pay rates—their landlords did—so these tenants were not automatically entitled to a local council vote. These rules applied only to local council elections; all adults were enfranchised for Northern Irish and UK parliamentary elections. Yet this system, combined with discrimination against Catholics in public housing, amplified the political representation of unionism. Ratepayers' provisions also entitled owners of commercial property to nominate special voters (non-ratepayers) for each £10 ($28) value of the property, for up to six voters.2 Given disproportionate Protestant ownership of commercial property, this, too, increased unionists' political representation (see Darby 1976). Furthermore, the practice nurtured a culture of patronage within unionism, as non-ratepaying Protestants were dependent on properly owners for nominations lo vote in local council elections. There was also a pattern of gerrymandering, whereby electoral boundaries were drawn to ensure unionist dominance, most strikingly in Derry. Policing and justice also operated in a biased fashion, with the Civil Authorities (Special Powers) Act 1922 allowing internment without trial.'
Brice Dickson (2010), a respected human rights scholar and advocate (he was a founding member of the Committee on the Administration of Justice and the former head of the Human Rights Commission), makes clear the underlying difficulty of approaching Stormont's repressions as human rights violations. Although these practices disenfranchised the minority, he explains, international frameworks that define human rights do not prescribe particular political or voting arrangements. In this sense, these frameworks offer limited tools. For Dickson (2010), stretching human rights principles to denounce the Stormont regimes practices obscures the essentially political nature of its abuses (15). Extending this observation helps clarify a central insight: rights conflicts were political from the moment of their emergence in Northern Ireland. Broader narratives took longer to emerge, such as identifying human rights violations as causes of conflict or, later, human rights culture as a cause of peace.
In the 1960s, however, political and economic shifts occurring through¬out western Europe dramatically changed the regions politics. A growing Catholic middle class and radicalized university students (from both Catho¬lic and Protestant backgrounds) challenged the regions governance. 'The civil rights movement they created, and opposition to it, became a catalyst, rather than a simple cause, for the conflict. The local movement combined tactics from both the U.S. civil rights movement and European student uprisings. These tactics were introduced at a moment of increasing local tensions, as nationalists and unionists, respectively, celebrated the fiftieth anniversaries the Easter Rising and the World War I Battle of the Somme.4