Communication is difficult, especially over text, and emotions can get strong as there is a lot of work involved. Software developers are not always the greatest diplomats. Well-intended constructive feedback is often read as criticism, and situations escalate. And for whatever reason people love picking sides.
At least Mbin seems like a healthy project now, and since Kbin.social went down for good it's hard to argue a fork wasn't needed. Hopefully Ernest is alive and recovering well - he did us all a huge service by creating Kbin and making it open source.