Gabriel's speech is ironic for a number of reasons. For one thing, he refers to "our" country, meaning Ireland. Yet it's clear that this is a man who doesn't feel much loyalty towards his native land. This earns him the opprobrium of Miss Ivors, who calls him a "West Briton," a term of abuse for an Irish Unionist. Gabriel goes on to refer to the reputation of the Irish for their great hospitality, which in the context of British domination is ironic indeed. In allowing themselves to remain in a state of political and cultural subordination to the British, the Irish have indeed been way too hospitable to their colonial overlords. Gabriel's unionism is a prime example of just such "hospitality."
Later on in his speech, Gabriel enjoins his audience to cherish in their hearts the memories of the dead. Yet when Gretta recalls the fond memory of her departed young love, Michael Furey, Gabriel gets quite angry. Michael, though long since gone, still remains a threat to Gabriel; his spirit lives on, acting as a stark reminder of the bloodless inertia of the "dead" above ground and the society in which they exist.
The speech that Gabriel Conroy makes to the assembled gathering, with all its ironies, contradictions and rank hypocrisy, is intended by Joyce to reveal everything that's wrong with Ireland, and why the country remains in a state of cultural, political, and intellectual stasis.