It wouldnt be weaponized. The UK can still buy these products. It is only that the sale would incurr an additional tax that has to be paid by the exporting company.
Also the EU supports the US in its sanctions against Iran and has supported the sanctions against Iraq, that killed more than half a Million Iraqi childrens in the 90s by affecting food and medicine. The reimposed sanctions have lead to drastic inflation for food and rising food insecurity in Iran.
So it is not a moral stance of the EU. It is purely strategical and i find a strategic response to invasion plans perfectly appropriate
How is it "weaponized"? A weapon can injure and kill someone. If the UK needs to pay more for vegetables they import from countries they deemed an invasion discussable for, then this is hardly "weaponized". If the UK fails to provide its citizens with normal goods then it is an expression of systematic failure. Also the EU used tariffs on food products to handle the trade war instigated by Trump. How is that not an appropriate response to plans of a military invasion?
The british government has more than enough money to cover for its people. Poverty in Britain is deliberately caused by the british government, not by a lack of wealth of the overall nation. Also Britain can still buy enough veggies from the US and China. They just wont be fresh.
Sounds like a great idea, I'm sure that'll be a top quality learning experience for the poor who are already facing a cost of living crisis, that'll really teach them...