Boris Johnson thinks it's mad to impose trade tariffs to punish other countries

It's crude paranoia to think the EU wants to "punish" Britain.
EU has enough future internal problems to worry about, without giving a damn what weirdness UK gets up to.
Johnson has gone for emotive language Trump style or his own Boris-foot-in-mouth-style.
Politics all over Europe is about consensus, not the adversarial system Britain thinks is normal.

Jonson is not a conviction politician who has any coherent perspective on anything. In fact, I don't think Trump is either. Trump just realised that the easiest way to get himself into office was - on top of being a racist, misogynist arsehole - to propose a loopy economic agenda of 45% tariffs and massive tax cuts. Now he's going to have to face up to the consequence of promising policies that will do the rust belt people he claims to speak for enormous harm.

Jonson's views on this sum up how contradictory right-wing economic ideology is at the moment. On the one hand they want open global markets, but at the same time protectionist policies. It's crazy.

Tariffs are a bit of a shoot in foot situation.

JCBs for example (the diggers) have significant amount parts which come from over seas. Tax those as they come into the UK and you make JCBs more expensive when you export them, same with most things made in the UK.

What was Brexit for? If you're out, you're out.
It's like giving it some time in a relationship.

As for the Orange Lord of the Sith, I hope he gets a reality check from Mexico and Chi-nah. China in particular has several tentacles around the world. The US is important but not fundamental.