This is not about obligation to fix bug reports. It is about respectful communication, which is pretty orthogonal.
No we can't agree on that. There is no obligation to be polite.
Of course I wouldn't expect people to love me for that, and it's not how I personally act; but if someone felt like acting in this way, it would be fully within his/her rights to do so.
My point is that the way he chooses to behave is in the long run damaging to the community that he founded and leads.
You are somehow deciding that collaboration is needed and wanted by every maintainer.
That's your (wrong) assumption.