Such studies are usually intended to give external legitimacy to pre-decided internal plans. So someone had them draw up the study, telling them what the conclusion should be.

There's also the opposite effect - that organisations pretending to be legitimate create "studies" to shift the Overton window a bit. In practice, most of these things go into the circular file anyway. If you go searching on pretty much any topic, there's pretty much all the possible opinions in the form of "studies" for the EC.

Keep in mind this study was commissioned by a work group of the European Parliament, not the EC.