My take on Ziewe's departure is that he, like most people of old age, are extremely entrenched in their views and resistant to conflicting worldviews. Speaking in neuroplasticity terms, he has hardened his neural pathways that involve his view of reality, or something similar. The poster's rather moronic accusation was registered as a challenge to his authority and experience, which prompted his rather hasty response.
The poster is a stereotypical example of the socio-economico-ecologico-political justice warrior hellbent on stalling any other research until the perceived wrongs of the world are solved. I am rather ambivalent to this attitude, which reeks of self-righteousness and naivete. The same thing is happening to SETI funding. As if finding out if there is any other sentient life on other planets or if there is truly an afterlife that we go to when we die won't make us better human beings in the process.