You could use exactly the same argument about the US, China or any other powerful state that ruthlessly defends accress and integrity of its internal market in negotiations with neighbouring states. It's an essential part of a state-building process https://twitter.com/TomMcTague/status/1337306575246143489

No one asks why the US is so tough in about access to its internal market because in the UK there is an assumption that this is normal for a great power. The bafflement over the EU using its power shows how many in the UK struggle with asymmetry of power where UK is weaker

Trade negotiations are not some kind of debate about moral behaviour.

Trade negotiations are a struggle for power, where the more powerful side usually gets more.

It is fascinating to watch how many in the UK who view themselves as hardnosed proponents of Realpolitik struggle in a world where they have Realpolitik done to them