I agree, it is a chain of poor responses to abuse, these people probably considered the original response that they got (along with having their pull request deleted) as an abuse which is why they responded in that way.

I don't really have any particular opinion on Moxie or Signal; I've never interacted with either the product, the community, or the person. But I will say in the abstract that many founders drastically underestimate how much extra headache poor community management will cause them in the long run.