I don't think the comic is claiming that all tariffs in any context are bad, that would indeed be a reductive, bad take.

Given the timing and the metaphor of blood being sent to and from a limb, this is almost surely a reference to the tariff threats against Canada.

Oh this is a good point. I was not aware of new developments with US-Canada today, that makes the more-than-normal stingy reactions expected.

Sorry, I'm European and can't keep up with the erratic US Gov. I read a summary at the end of the week.