Earlier quoted context omitted.
They are appointed by the elected(the governments of the countries and the European Parliament, which are all elected). When you say it like "they are not elected but appointed", you make it sound like some 3rd party is appointing them and you have no power on it but those who appoint the members of EC are the members of EP(elected every 5 years) and the national governments(elected accordingly to the local laws). If…
"They are appointed by the elected(the governments of the countries and the European Parliament, which are all elected)." The executive (governments) should not become legislators, under the principle of seperation of powers of Montesquieu.
What if Montesquieu was just wrong and systems with fused or subordinated executive and legislative powers actually just work better in pretty much every way that separation-of-powers systems?
Yeah, the US unusually strongly applies Montesquieu in its Constitutional design, but the US isn't particularly well-governed among modern democracies. (Personally, I think the dominance of poor electoral methods and the resulting partisan duopoly is a bigger effect than separation of powers here, but...)