I don't understand that part either
The EU wants Britain to keep to the terms of the Good Friday Agreement.
One of the terms of the Good Friday Agreement is that there be no hard border between the Republic of Ireland and Northern Ireland.
In order to avoid a hard border, there needs to be no significant economic reason to smuggle goods between the two areas.
This means that the two areas need to have the same tariffs, standards for products and so on.
In other words, Northern Ireland needs to be part of the EU Customs Union.
The British government’s position is such that they can’t agree to any permanent situation: they’ve ruled out the entire UK being in the Customs Union, DUP opposition means they can’t accept Northern Ireland being in the Customs Union without the rest of the UK, and Northern Ireland not being in the Customs Union would require a hard border.
The backstop is a pretense: Northern Ireland will be in the Customs Union ‘temporarily’, ‘if no other solution can be found’. Both parties know that there is no other solution, but it allows the British government to say that they don’t like what’s happening either, and that it’s just a temporary situation while we negotiate something better.
Unfortunately Brexiteers have realized that it’s a trick, but have blamed the wrong side: they tend to characterize the backstop as the EU tricking Britain into staying in the Customs Union.
The EU want what they want because
i) the Republic of Ireland wants it, and if the EU failed to support the Republic of Ireland against Britain, Poland (for example) might wonder what would happen if it had a dispute with Russia. Membership of the EU would therefore become far less attractive.
ii) The Good Friday Agreement was a demonstration of the EU’s ability to bring peace to Europe.
iii) They probably would rather not have the Troubles come back.
SO AT THE END OF THE DAY EU DOES NOT WANT THE IRISH PEAPLE THROWING TATTYS AT EACH OTHER ,LOL.