The problem here is that a lot of themes are allegedly being released under a GPL-compatible license (so they say) with terms that are actually incompatible with the GPL. It’s simple. You can include a footer link or other self-promotional element but you can’t prevent a user from removing it. Section 2 of the GPL (v2) explicitly permits unhindered changes, so long as you do not deny that same right to anyone you distribute your modified version to.
Many of the themes removed were attempting to impose exactly this restriction, which is violating the license of the themes in question. This raises at least two questions:
- In the case of original works, why would the author opt to license their works under the GNU General Public License if they did not intend to honour the terms of that license?
- In the case of derivative works (basing one theme on another theme, or reusing portions of the code in another theme), do theme authors not read the licenses for the code they are modifying? They are bound by the terms of those licenses to allow changes to their derivative works.
It isn’t like Section 2 is ambiguous about derivative works:
2. You may modify your copy or copies of the Program or any portion of it, thus forming a work based on the Program, and copy and distribute such modifications or work under the terms of Section 1 [...]
The referenced part of Section 1 in that excerpt is:
1. You may copy and distribute verbatim copies of the Program’s source code as you receive it, in any medium, provided that you conspicuously and appropriately publish on each copy an appropriate copyright notice and disclaimer of warranty; keep intact all the notices that refer to this License and to the absence of any warranty; and give any other recipients of the Program a copy of this License along with the Program.
Simple terms, right? You can change or build on the code (or parts of it) and distribute those changes, as long as anyone you distribute it has the same rights you had. Creative Commons licenses refer to this as a “share-alike” provision. I’ve heard it called Viral Licensing before, which is the most appropriate descriptor.
This ability to adapt and remix code is where open source code draws much strength from. It permits rapid change, unsolicited contribution, and forking of abandoned works (or works where one or more contributors decided “I can do X better”).
If you do not appreciate the freedom GPL grants to users of your software, release it under a different license.
I applaud Matt and the crew at Automattic for their courage in enforcing this. I am certain they anticipated much of the unreasonable backlash they would receive, and chose to press on. If forced to choose between what is easy and what is right, the question should not allow more than a moment’s thought. And even then, only to question why we hesitated.