So it has nothing to do with reciprocality but it's simply 10% or the trade deficit, whichever is larger?

"Who makes policy this way? The key point is that Trump isn’t really trying to accomplish economic goals. This should all be seen as a dominance display, intended to shock and awe people and make them grovel, rather than policy in the normal sense."

Spot on. It's mob boss / bully tactics.

Appeasing bullies does. not. work.

That graph of the average US tariff rate over time, which I also saw in a BBC article, really brings home how seismic a change Trump's tariffs announcement is.