Yes, we are all investors, but some investors are more equal than others.
We all want the platform to do well, but there are some trends out there that advantage one type of Steemian over another. And it could be argue these trends are detrimental to the Steem economy as whole (maybe in the long-term if not the short-term.)
From a different angle, if we are all investors (versus writers, content-creators, curators, etc), it makes it very difficult to defend against the criticism that Steemit is a giant ponzi scheme.