Almost everything that gets written has an agenda behind it.
Newspapers are owned by often wealthy people who want their opinions voiced and most newspapers will not write anything to offend a sponsor/advertiser. This is the same online.
Whatever we are reading there is an agenda to a greater or lesser extent, yet we seem to view articles or posts as if they can be the only version, the only voice, how it is. We seem them as definitive.
Often, the agendas are hidden and what things seem on the surface is not the real message being sent.
The thing is as long as we realise there is an agenda, then it is our choice as to how we interpret it.
But rarely is anything completely objective.