From my perspective, it isn't a desire to police tone. I am not the 'kindest' communicator myself, I don't get offended easily, and I do enjoy debate.
You don't have to be kind to welcome people into the movement. Civil would help though.
The intellectual superiority and the insults are not robust debate. They're... arrogance? Impatience? Contempt? I've been accused of being a man many times in conversations like this, on this board, because I simply can't be a woman, because a woman wouldn't hold my views. I think a couple of people have intimated it on this thread, actually.
I've also been flatly told I'm not feminist, because I 'include men'. My own interpretation of feminism has never been in opposition to men - it's about women being equal, not opposed. My opposition to the patriarchy comes with the recognition of the harm it does to men, as well as women. And while being told I am not a feminist is fine, because there are many sub-sections of feminism, it inevitably means that this branch of feminism is not for me - because you're explicitly telling me it's not, from the get-go.
I also get the impression that many people don't want to welcome different voices into the group. That's what I mean by ideological purity. Someone upthread asked why safeguarding is 'ideological purity'. It isn't. Different approaches to safeguarding can surely be entertained and discussed though? It doesn't feel even worth entering the conversation now - so many of you are in a settled state in your minds, which is fine, and you don't have the patience to bring anyone on a journey. Also fine - it's not your job to educate anyone.
But it does rather leave gender critical feminism feeling like a closed circle. Also fine - I only joined this conversation to suggestion why people aren't engaging more, as per the original question.