This is a question of judgement, there is no black and white answer. The council agreed to exclude the public, and you have to consider the reason for this. Was it commercial confidentiality? Was that justified?
If a decision was made, then it must be minuted and the minutes are available for inspection by the public. The minutes may avoid going into detail, but must identify the fact that a decision was made and give a clear indication of what it was. Without that, the decision was effectively not made.
There is, thus, a limit on what is confidential, and you are entitled to review just what exactly the council is seeking to keep confidential. If you were to go public on issues that the council had good reason to keep confidential, then you would be in the wrong. But if you discuss matters that are more general than the information the council sought to keep confidential, or you judge that the council was being unreasonably secretive, then you would be in the right.