Hey, thanks for your feedback.
But it is still weird to see many distributors hang around Itch.io
There aren't that many publishers on itch.io. Plug in Digital and 4EversGames are actually related companies, the second started by someone who originally worked with Plug in Digital. They just moved their business over.
We don't encourage publishers or seek them out. We always try to get the original creator of the game to post. In this case, the two accounts above only provide Steam keys for their products, and we would much rather have people uploading DRM free versions of the games.
Sometimes developers are hard to convince though, since they don't have the resources to put their game on another platform. In those scenarios, a publisher may be the only way to get a certain game on the platform. We're not going to ban publishers since there may be people who want to support itch.io by buying a certain game, and a publisher may give us more opportunities for that. If we feel like there are too many publishers getting in the way of the developer's content though, we may change our stance.
We haven't added any special code for publishers, but I think in the future it would be useful to make it clear that they are not the developer of the game, if you're worried about people being confused who they are buying from. Additionally, I'm worried about how they're selling DLC, since it's not clear at all that you have to own previous content. We'll need to get in touch with them about it. Thanks for reporting it.