I skimmed that article for evidence of your claim that free trade caused the Irish potato famine, but couldn't find any. It seems to discuss "[the assumption] that, had this event [the Irish Potato famine] not happened, Britain would not have repealed the Corn Laws at that time, and thus, would not have taken steps towards free trade in subsequent years" and concludes that "Britain would have moved towards Free Trade in 1846-1860 even if the Irish Potato Famine had not occurred".
The article doesn't seem to concern itself with that aspect at all? And the famine predates the repeal of the corn laws, to the point where the famine was an explicitly cited motivation for the repeal.
