If that is the case, then discussion about PlayOn (not involving Hulu) would also be allowed, but it is not.
PlayOn comes with Hulu support natively. You don't have to add a plugin to enable it. Its primary use is for access to online content that isn't otherwise available on mobile and STB platforms (95% of which violates the TOU of that content), whereas Plex is primarily targeted at local content playback.
Plex actively markets Hulu support as well. Check out their iPhone app page in the iTunes store. There is a Hulu logo right on the screen shot.
A logo in a screenshot for an application on a different platform hardly constitutes "actively marketing". If you want to insist that it's marketing at all, then it's passive marketing at best. I receive no less than three emails a week from PlayOn advertising support for different online content (rarely, if ever, its local content features). I've never received a single email from Plex.
Based on your join date, and your posting history, I don't think you were around when the whole PlayOn thing happened. They are solely responsible for the ban on discussions here. When they were informed by Roku that the channel in its current state violated the developer's agreement (and potentially received a DMCA complaint), instead of working with Roku to make it acceptable, they chose to not only ignore Roku by re-publishing the channel under a different code, but also posted the source code and private channel publishing instructions on their website, so they could essentially have their users flood the channel store with different private channels to make it impossible for Roku to pull it. All the while, they continued to send out marketing emails and advertise on their website to make it look like they were partners with Roku.
Plex, on the other hand, chose to work with Roku to ensure they could release a channel that was acceptable and did not violate any agreements, which presumably included filtering certain plugins from appearing in the Roku channel.
I'm not really sure why it's such a hot topic with you or why it bugs you so much, but the bottom line is, no matter how many times you post about how unfair it is, discussion of PlayOn isn't allowed here, which isn't likely to change. I'm pretty sure that ship has sailed...