What he means above is 'Unionists/Loyalists', not 'protestants'. He falls into the old trope of equating religion with political opinion/national identity in the North of Ireland. Easily done considering protestants mainly identify as British and Catholics mainly identify as Irish if you were to simplify things but there are a mulitude of grey areas and political leanings. Such language inadvertently cements sectarianism. The 3rd biggest party in the most recent election was the Alliance Party who don't take sides on the constitutional question and whose voters are largely made up of middle-class protestants who would accept the result of a referendum on Irish Unity either way.
As for the Irish leading, it's a rosey-tinted picture he paints. While the Irish state has a proud tradition of nuetrality and non-alignment, in reality it's culturally the most Americanised country in Europe and one of the most pro-EU. While not a member of NATO (for now!) the levels of anti-Russian nonsense coming from the government is grotesque. Sinn Féin have been very timid in this pro-war atmosphere and if you were to look for a strong anti-war and anti-imperialist stance you'd be better off looking at independent socialists like Clare Daly and Mick Wallace in the EU parliment for inspiration.
At the end of the day Sinn Féin are just another 'left wing' political party like Syriza or Podemos who will capitulate to neo-liberalism in the blink of an eye to get on board the gravey train of governance. They've been doing it for years in the North of Ireland where they've power shared in Stormont, implementing neo-liberal policies and blathering performative nationalist platitudes (while doing feck all for working people, meaningful promotion/support for the Irish-language, etc).