Point 1. You can't just amend GPLLinuxSampler is licensed under the GNU GPL with the exception that USAGE of the source code, libraries and applications FOR COMMERCIAL HARDWARE OR SOFTWARE PRODUCTS IS NOT ALLOWED without prior written permission by the LinuxSampler authors. If you have questions on the subject, that are not yet covered by the FAQ, please contact us.
Here: https://www.gnu.org/licenses/gpl-3.0.en.html it says:
You can't just change GPL.Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.
Point 2. Prohibiting commercial use makes the software proprietary
A software is free if it gives 4 fundamental freedoms to it's users. https://www.gnu.org/philosophy/free-sw.html
Prohibiting commercial use removes freedoms 2 and 3. Freedom to redistribute and freedom to distribute modified copies.
Point 3. You can't link GPL and proprietary software together.
Again, here http://linuxsampler.org/downloads.html it says that LinuxSampler links to libgig and this is mandatory. LinuxSampler is proprietary, libgig is GPL and GPL prohibits linking to proprietary software. So the LS devs breached the GPL and commit copyright infringement.
What can you do
- Contact the devs and inform about this. I've tried to register on their forum but it seems to have many anti-spam features and my posts are yet to be published.
- Remove LinuxSampler from repositories. I urge anyone who maintains a Linux distribution to remove LinuxSampler from their repository or at least explicitly mark it as non-free.
- Remove references to LinuxSampler from http://libremusicproduction.com/ I've already contacted them but have yet to see the reply.
- Contact organizations that deal with GPL violations, such as http://gpl-violations.org/ If the devs are not going to change the licenses, a legal action must take place.