LOL!
Let's consult your source:
"As a devout advocate of laissez-faire, Trevelyan also claimed that aiding the Irish brought 'the risk of paralyzing all private enterprise.' Thus he ruled out providing any more government food, despite early reports the potato blight had already been spotted amid the next harvest in the west of Ireland. Trevelyan believed Peel's policy of providing cheap Indian corn meal to the Irish had been a mistake because it undercut market prices and had discouraged private food dealers from importing the needed food."
So this is the scenario:
John Peel temporarily revoked the protectionist tariffs that kept cheap Indian grain from being made available to the Irish market.
Trevelyan was worried that the inflow of all this cheap Indian grain in Ireland would hurt the ability of the landed grain growers of the UK to keep their prices artificially high.
So Trevelyan moved to put back the protectionist barriers in order to keep cheap Indian grain off the market, so that UK grain prices could remain artificially high.
You and the author of your source clearly do not understand what "laissez-faire" means.
A true laissez-faire policy would have been to allow grain merchants from any nation to sell their wares in Ireland at any price they wanted, whether or not it hurt the profit margins of protected English land barons.
You and your source have inadvertently confirmed that intervention slaughtered the Irish, when free markets could have saved them.
The Corn Peel arranged to purchase was government bought, and was paid for because it was not a foodstuff that was in any previous demand, so would not, the theory went, interfere with existing markets.
To Trevelyan of course, government expenditure was government expenditure, and thus he opposed even this inadequate intervention by the state.
Trevelyan wasn’t advocating tarrifs, he was advocating as little government intervention as possible, and hoping that under free market conditions, the food would be cheap enough to stave off the famine....
By the way, the Tory PM was called Sir Robert Peel, not John Peel. Was that an elementary mistake, or a typo on your part?