Diana Johnstone, a former Green staffer at the EU, does some good reporting on this larger issue.

https://blackagendareport.com/german-greens-crusade-usnato-wars

https://consortiumnews.com/2021/05/03/diana-johnstone-washingtons-green-branches-in-europe/

It's also maybe not quite accurate to call Joschka Fischer the "father of Green pacifism" as in the original piece linked. He was a huge cheerleader for the NATO bombings of former Yugoslavia in the nineties, ironically enough one of the international legal precedents Putin is using for the special operation in Ukraine now.