So, I found myself in a similar position recently with a technically FOSS project. The patches I was submitting were being re-licensed under a commercial license and sold to enterprise customers. I had to sign contributors agreement before sending patches and after the fact I found myself having a philosophical issue with them selling my work. As a consequence, I stopped submitting patches to the main project and instead maintain my own patch repo now.

While I find the wholesale re-licensing of the codebase under a commercial license reprehensible, I agreed to that before committing code. That leaves me with one remedy, not committing additional code.

As a side note, this project had a basic FOSS version and an enterprise version with additional functionality. The only part of what they did that I took issue with is re-licensing the FOSS portion under a commercial license. Had they left the FOSS portion under the OSS license and simply added commercial code on top I would have 100% continued to commit patches.