why do companies have to sign a confidality agreement to peek in the room what is in the room that shareholders don't know and if there is info we don't know why the f $$$k not

Companies are allow to keep confidential or secret even from share holders, material information which is deemed strategic or for which they do not want competitors to get a hold off. For example 2D seismic data is acquired at great cost to the company, and as such is an Asset of the Company. Quite obviously it would not be in the interest of the company to make such document public, when after all they could sell it for a premium to what they paid to have it done.
However, in this case here, for a potantial acquirer to get an understanding of the Oil field, he would want to look at the 2D seismic data - hence the requirement for a confidentiality agreement.
Then you have the full details of the OML agreement with the Nigerian government - such are not published document - rarely will a company divulged all the I's and T's of a contract, but it is made available in a dataroom.
Planning and route of a pipeline might also be deemed startegic and proprietary information, hence again not public domain information, but revealed in a data room.
I could go on and on , but I'm sure you get it.