There is no obligation to collaborate either. I can write a software, publish it and insult people who wrongly report bugs.

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.

RMS has the right to behave as he wants. He is not obliged to behave in a particular way.

My point is that the way he chooses to behave is in the long run damaging to the community that he founded and leads.

I replied to a comment saying "a maintainer". If you had unilaterally decided to change topic without informing me… well in the future try not to do that.

Not a change of topic. Rudeness from a maintainer is equally corrosive.

No it's not "corrosive".

You are somehow deciding that collaboration is needed and wanted by every maintainer.

That's your (wrong) assumption.