Because now we Canadians have to pay for their debt they've accumulated.
First off, we don't HAVE to pay it.
Second, the amount recovered won't make the tiniest difference in the debt.
Third, who cares? The US is a foreign country. If they choose to impose fees on visitors, that's their option. Either you're willing to go visit, or you're not. Many countries require entry visas, that cost money.
People in this country must be well off if they feel it's important to whine about this.