What the DUP are complaining about is a direct result of their own intransigence over the Customs Union which helped get rid of May. They helped put Johnson in place and voted for the Withdrawal Agreement with the border in the Irish Sea and are now crying over the result.
Simon Coveney the Irish government’s Foreign Affairs Minister explained it simply a month ago when Johnson threatened to invoke Article 16.
“The problem is caused by Brexit, and the kind of Brexit that the British government pursued and insisted on, because there were alternatives that would have been much easier to implement, the EU wanted to share a customs union and single market with the UK, that would have meant no barriers to trade.
“Some people are trying to rewrite history here … the protocol itself is about solving problems that are caused by Brexit, trying to protect an all-island economy, prevent border infrastructure on the island, or tense political relationships on the island.”