I know that Mr Shatter is Jewish, I believe he is the first ever Jew to be an Irish government minister. I don't know enough about him to know whether he can fairly be called a Zionist, but I'll take your word for it.
I hold no particular brief for the state of Israel, but whatever one's views on the actions of a state which wasn't formed until 1948, they seem irrelevant when considering the fate of the Jews attempting to escape Nazi oppression in the 1930's. There seems little doubt that Ireland's refusal to offer asylum to Jews at this time was in no small way influenced by the Catholic Church, whose attitude to the Jews in those days can at best be described as ambivalent.
As a Roman Catholic of Irish extraction I feel ashamed of both Ireland's and the Church's record in this area, and wholeheartedly agree with Mr Slatter's statement.
With reference to the MS St Louis, it should be noted that the United Kingdom accepted 288 of the 930 refugees who returned to Europe after its abortive trip to Cuba, the USA and Canada. I am not aware that Ireland took any in.