If that's true, then all criminal law in the US is foreign policy because the existence of laws restricts people's decision to visit the US to commit crimes.
Hell we don't even need to go that far afield: your logic implies all taxes are foreign policy, as they all affect foreign trade.
The policies you mention don’t target particular countries, and this is where the difference lies in my opinion. The part of the policies which is countries specific is in fact foreign policy.
I don’t think tariffs being foreign policy gives the president full control over them because foreign policy is presidents responsibility. Tariffs have this duality between being foreign policy and budget. So I don’t have issue with Congress delegating some of the tariffs power to the executive in some circumstances.
No, because criminal laws don’t have the primary function of influencing foreign countries.
Taxes can be for raising revenue, but they can also function as clubs for changing behavior. Cigarette taxes, for example, have the purpose of deterring people from smoking.
Tariffs similarly can serve as clubs against foreign countries. You might have a tariff on China to get them to change their domestic policies. In that capacity, the tariff is functioning as a foreign policy tool; the revenue generation is incidental.
Exactly. The same nonsense-logic for collecting these taxes could be abused to bypass Congress and give away zillions of taxpayer dollars to anybody (including his own companies) that go: "I just bought lots of Trumpcoin to be patriotic, and I ultra-promise not to do business with Iran or Venezuela or whatever."
Aside: I recommend the phrase "import taxes" over "tariffs", because a disturbingly large portion of my neighbors still don't seem to understand WTF the latter really is.