I saw I did not really explain the reason: The EU is full of hidden conflicts - Germany vs France, southern countries vs northern countries, former east bloc countries vs southern countries, and of course the Commission vs the national governments/voters.
One way to keep these potential conflicts hidden is continuous enlargement. And then there are many europhiles who are dreaming about making the EU into a global superpower.
Now, you may well ask (and you already did) how can the membership of an economic basket case, super corrupt country, who also is part of the largest military conflict in Europe since WWIi strengthen the EU?
It won't and it can't, but it may (at least in the short run) increase the power of some EU administrators - and possibly cause some very short term increase in popularity of some European politicians.
They do not have any better reasons than that. We are governed by very unserious persons.
(Note that once again MSM is very guilty.)
Some good insights, thanks…