Where in the fact picture that Canada's leaders didn't understand their seafood markets or petroleum infrastructure is the Trump administration's understanding of Lesotho?

In the point where the fact that Trump imposed high tariffs on coffee and diamonds didn't mean that he doesn't understand how coffee and diamond markets worked. It just means that when you adopt a tariff structure for one type of purpose, but it covers untold numbers of products, you are very likely to include a segment or two where that specific segment ends up causing your economy more harm than the purpose you're trying to achieve. It's too massive an undertaking to get everything right on the first go unless you spend months and months analyzing it in advance. Which Canada didn't have, and Trump didn't bother to do.

As for the oil infrastructure, Canada's well aware where most of their oil goes. They're also well aware that Trump's war in Iran means that we have to keep buying that oil, and can't use it as leverage in tariff negotiations. Why? Because oil and gas prices are already higher than where the Administration wants. Americans are already screaming about gas prices. The world markets are already on edge about oil supplies. Trump's already trying to jawbone the refining industry to do something to help him out on this, and so he can't blow up their massive dependence on Canadian imports as feedstock for their operations.

If anything, the constant pointing to Canada's oil infrastructure illustrates that the critics don't understand our refining infrastructure and oil markets - not Canada's ignorance. Canada knows we can't and won't shut off those pipes.

This is just trying to backfill something - anything - to justify the Administration's idiotic choice to rip up the trade deal with Canada in the foolish belief that we could just serially strong-arm them into accepting worse and worse deals. Trump isn't doing this because Canada is soft on fentanyl, or illegal immigration, or economic security, or whatever reason of the week they're giving now. He's just mercantilist at heart. He wants the tariffs because he wants the tariffs. He believes that any trade deficit means you're "losing" that interaction, and wants big tariffs on Canada because they have a trade surplus with us (see the oil above) and he believes that if we bully them enough they'll just do what we wan.

Canada is smart to be taking the approach they're taking. They've stood up to that negotiating tactic. Trump's supporters want to believe that Canada is doing something dumb. Yes, when Canada put together a defensive retaliatory tariff structure in haste because of Trump's foolish act, they assembled it based on damage to the U.S. economy and did not fully gut-check if there were any industries where the pain to themselves wasn't worth the cost - just like coffee and diamonds on Liberation day. But they corrected it on the fly, and generally they've maneuvered pretty well against a President who doesn't understand that Canada holds some important cards in these negotiations.