It's common in European manufacturers not to grant full access to kosher certifiers to all areas of the facilities, nor to all of the ingredients, processing agents, equipment, etc. Therefore they created the "It's on the LIST".
"Rabbi you can't go past this point, you can look through that glass door or window". It's pretty common in Europe by many (not all) kosher certifiers.
The the educated kosher, this is totally unacceptable kashrus. If they would refuse to purchase anything on the "list" nor product that there isn't FULL access, this attitude would change very quickly.
Many of the European kashrus agencies do not respond to consumer or other organizations queries re: their standards, detailed questions (of course we can't divulge confidential info).
The reason they don't respond is that many items they just don't have all of the required verified information, so just don't respond to any inquiries.