AI Safety researchers and AI Capabilities researchers are part of the same community because they both believe that the long-term goal of humanity should be a technological utopia, and the most useful tool for building Our Glorious Future is AGI.
Your understanding of degrowth is not correct.
Most degrowth researchers are acutely aware of the issue of why they advocate reduction of economic activity.
Please read up on this:
that will likely help separate "green growth" environmentalists out from what you discuss