The potato blight was a natural disaster.
The famine was caused by the British exporting the same amount of potatoes out of Ireland as before.
They didn’t export potatoes out of Ireland, they exported everything else. Meaning there was no other food but potatoes for the Irish to eat.
The Irish at the time also grew wheat and meat and everything else that was grown on the British Isles back then. The problem was the colonising English owned all the land and exported all the food
Potatoes were the emergency food, the only thing Irish could grow and eat
When Irish were dying of starvation the farms they were forced to work were growing plenty of wheat and sheep