Degrowth is a popular concept among solarpunks. This Jacobin article discusses some of its flaws from a Marxist standpoint. In particular, Jacobin reminds us an interpretation of Marxism which blames the Western working class for exploiting the Global South, and lectures the ever-more-exploited Western worker on the need to consume less, divides international labor against itself and sabotages its own best hope of success.
I do understand the sentiment but I would urge that we need all the voices of discontent towards the current system to be united if we even stand a chance at the change we need on the timelines necessary.
I agree that solidarity and good faith dialogue needs to be two way and it can be difficult at times but we must keep striving to find a way of working with those voices.
Also, should go without saying but you shouldn’t judge a person by their fans (or really a subset of them). Lots in Marx has relevance and resonance to the problems we face. Solarpunk without class analysis will be subverted into techno-captialists vision for the future.