It really should be termed the EU Military as it's not just the armies of the EU that they want amalgamate, but the navies and air forces as well!
They are telling us that it is necessary to spend billions of tax Euros on the establishment of an EU military command structure (basically replicating NATO) for the defence and security of Europe, but it has been proved 3 times in the last hundred years that we cannot defend Europe from each other, or from a large external threat like the USSR without the help of the USA.
NATO has done a great job in the last 70 years, so why do anything to jeopardise that?
Firstly, they say that Trump is threatening to pull out of NATO so we cannot rely on the US, but Trump is only going to be around for another 6 years max. Maybe less, maybe a lot less!
Trump's bluster is more about getting European countries to spend more on defence, than any serious threat to walk away. You have to keep that threat to walk away though right?
Secondly, amalgamating the armies. navies and air forces of the EU into one force, with a single command structure controlled by the EU then gives the EU the ability to project hard power..... in the EU's name.
And this is what it is really all about IMO.