I don't understand your point. The EU and all of the stuff associated with it was part of the agreement. Brexit was the UK backing out of that agreement, which means now they need to negotiate with individual countries (and the EU as a bloc). Which means now they need to figure out how the borders are going to work, how immigration/travel is treated, how imports/exports should be treated etc.
Why is it baffling that they need a deal when that's exactly what they wanted? It sounds like you want the ability for a country to leave the EU, but then not have to negotiate all of the benefits that came with being in the EU. Which, isn't exactly how it works.
As a similar analogy, it would be like if one of the states here in the US successfully seceded. The US would be under no obligation to make deals with said state, they would have to negotiate as two separate countries and all of the geopolitical stuff that comes with it.
Why is it baffling that they need a deal when that's exactly what they wanted? It sounds like you want the ability for a country to leave the EU, but then not have to negotiate all of the benefits that came with being in the EU. Which, isn't exactly how it works.
As a similar analogy, it would be like if one of the states here in the US successfully seceded. The US would be under no obligation to make deals with said state, they would have to negotiate as two separate countries and all of the geopolitical stuff that comes with it.