> everyone agrees that it's good for a country to export lots of stuff
Not if you want to avoid escalation of a trade war.
If you know that the US is pissed off because you're hoarding dollars because its the reserve currency and its causing the USD to rise too high, leading to their decline in manufacturing competitiveness, then you can solve their problem for them by adding an export tariff. It will make them more competitive. But that way, you get the revenues from the tariff rather than the US. Adding your own import tariffs makes the trade balance worse. Its like the person you're negotiating with is complaining about a knife and you decide to twist it rather than remove it. A 50/50 split of export and import tariffs would mean that both countries can take a cut, the USD can maintain reserve status, and US manufacturing can stay competitive despite a stronger dollar. The fact that noone is doing this means that either they haven't considered it or they aren't happy with this outcome(probably the latter, but you never know...)
> If you know that the US is pissed off because you're hoarding dollars because its the reserve currency and its causing the USD to rise too high
But you don’t know that! The explicit US position is that their tariffs are purely retaliatory, based on a formula they invented a few days ago which claims to compute an effective rate consisting of tariffs and non-tariff barriers. Export tariffs would make the formula as currently constructed go down, but the US would clearly see you’re juking the stats rather than actually removing trade barriers, and adjust the formula to account for it.
Perhaps you think the US is being strategically deceptive about its motivations? I do see a lot of people offer that as a “defense” of the US position, although I don’t clearly understand how this is meant to make things better. How should foreign trade negotiators know which HN commenters are telling them the real position and which ones have been taken in by the misdirection?