Well it's not an issue of doing anything wrong, but I think most people like to know who is in charge whenever they join an organization or work for a company.
The name of the owner is in the upper left corner of the site. Whomever does work for him by proxy is self-evident when you do something wrong.
Joining an org or working for a company is not what's happening when you post on a website so the comparative argument you pose is not relevant.