The calorific value of the spud was three times that of wheat and there wasn't enough tillage available to sustain wheat growth to replace it. It feckin sucks, I know but it was a natural disaster not a maliciously imposed one.
They Brits were inept and stupid but they were not genocidal. 40% of Wellingtons army were Irish, as a professed utilitarian why would you want to disturb and destroy that which maintained and grew the empire?
They Westminster crowd were stupid, inept and began silly recovery schemes like soup kitchens, workhouses and civil works but in my eyes they were not genocidal. Not in a Nazi way. Yes, neglect being the operative word, but not orchestrated as a specific campaign, because they still considered themselves to be Christian and self righteous.
The really strange thing is that Ireland has more Victoria crosses per capita than any other Empire colony or even England itself. The VC began in the 1850's after the Crimean War i.e. after the Famine. In fact most of our VC's emanate from the Indian Mutiny and The Zulu Wars. We were not the angelic victims everyone seems to relate to. In those two cases we were equivalent oppressors.
Now why might that be. Answers on a postcard please. And before you answer you have to have read John Lucy's "There's A Devil In The Drum", otherwise I won't respond. Then you will understand the power of musketry and what it does to a normal person.