As a point of fact, it isn't true that the dominant currency imposing costs is new...that has always happened. Britain did it in order to secure continued use of the £, and the US has done it before now. It is a normal extension of foreign policy (because finance is not separate from politics, as the Rusal example shows). It isn't some kind of authoritarian aberration either. The point is that the US has most to lose…
I've subscribed to the Economist for the past five years (or so). It's sad to see their decline. About 90% is still good, especially when they focus of international news. But they're willing to publish lower quality articles when defending their official liberal position. Sadly, the occasional low-quality article is seeping into other areas.
I actually wouldn't say it is about having an official position either. The OP really isn't about liberalism vs illiberalism...politics/finance are inseparable and the US is the guarantor for an open financial system. The article ends up arguing for the position of Iran/Russia/China (and the illiberal voices within the EU like Juncker) who extract from the system without paying in. You can't respond to illiberalism with liberalism. Imo, this is a fairly obvious aspect of international relations that, in the past, the Economist rarely missed. But since the switch in editor, it has become: our goal is Trump bad, let's write an article that shows this so we will get there any way we can.
It isn't only Trump though. In other areas, writers dispense with liberal values whenever it suits (which is increasingly common these days).