So basically, fighting climate change is now a racist activity.
I don't think that it's implied that it's a racist activity... Unless you meant something like "race is now an important factor in fighting climate change".
Which makes me wonder,
a) Why BIPOC were seemingly excluded in the first place (structural issue? or was it just not diverse enough at the start?)
b) Why the diversity of the group was relevant at all
c) What sort of internal politics led to this decision
d) How this helps BIPOC... Or how they will include them going forward
Of course, I don't think anybody outside the group can really know what's going on internally. I feel like this news may be somewhat sensationalized---maybe the previous administration could be working towards restructuring the group, or another group could take its place. Can't really tell either way.
Very odd phenomenon nonetheless.
[Edit] A quick read of the facebook post (which I should've done at the beginning) makes it seem as though they're just disbanding in favour of other groups, so I don't think it's necessarily a bad thing; there are alternatives there. Nothing was lost but one administration.