Some Romanian politicians (example) argue that the country should be within the Schengen area.
I do not know exactly for Bulgaria, but for Romania I have heard on multiple occasions that it obeys the "technical requirements" for being part of Schengen, but it is still not enough (source or source):
several Schengen countries expressed concerns regarding corruption in the past. Although Romanian met the technical requirements, it's no use to have the latest technology systems if the people in charge of them are easily corruptible. Thus Romania was postponed entry and European Commision monitoring was established.
Bulgaria's and Romania's bids to join the Schengen Area were approved by the European Parliament in June 2011, but rejected by the Council of Ministers in September 2011, with the Dutch and Finnish governments citing concerns about shortcomings in anti-corruption measures and in the fight against organised crime.
While many cannot deny the corruption related problems, it seems strange not to include them in the "technical requirements". E.g. Mechanism for Cooperation and Verification could be used to assess progress with corruption and fight against organized crime. Being postponed due to not meeting a technical requirement seems much easier to understand than due to non-technical (i.e. political) reasons.
Question: Why are Romania's and Bulgaria's reasons for postponing entering the Schengen area considered non-technical?