Kritiq, you misunderstand me when you say; In short, there are many, many women who could feel marginalised and excluded from a definition of woman or female that is predicated on reproductive function, whether or not that is the intention of using such a narrow definition.
I am not defining women according to their actual individual ability (or desire) to have children. A post menopausal woman is a woman, a childless lesbian is a woman, a woman who is infertile is a woman.
I do not use a narrow definition of what it is to be a woman - I use the biological definition that a woman is a person with XY chromosomes and who usually has female reproductive organs. Of course these organs may not all be there in intact working order. A woman who cannot or does not want to have children, still has XY chromosomes and is still a woman. She belongs to the biological group which bears children even if she does not actually bear children herself. This is basic biology.
The reason I talk about reproduction is not because it is how I define all women - it is because it is the primary reason for woman as a group being oppressed.
If you think there is another reason for the global sex based oppression of women then I would be interested to hear it. We suffer sex based oppression due to our sex - our biological sex. I would have thought this to be quite obvious.
Male violence is one of the tools of that oppression - but that does not mean that all male violence is directed towards fertile women in relation to their fertility. It means that male violence exists as a global reality in order to globally keep women in line because globally we are the group that bears children. A side effect of this is hyper masculinity and a general effect of male violence that may not always be directed at fertile adult females (humans being complex and socialization being a complex process).
The gender binary hierarchy exists in order to oppress and control women.
Transpeople also suffer due to the gender binary hierarchy, because they don't fit into it - but the gender binary does not exist with the specific purpose of oppressing trans people. It exists with the specific purpose of oppressing biological women. That it then, as accidental fall out or a side effect, also oppresses trans people, men, homosexuals, etc is very true - but it is not the reason for its existence.
I am not a feminist because I am afraid of losing anything 
- I found your comment about that very odd, perhaps you misread the post of mine you were commenting on. I was referring to the very specific situation of how transpolitics appear to be affecting the very definition of woman. I am a feminist who does not accept that MTF trans people are biological women. I do not accept this because otherwise I lose my biological identity and therefore the ability to claim that I, and all women globally, are oppressed due to our biological identity. Like I said, game over for feminism.
That has nothing to do with a dislike or whatever of trans people. I wish them every happiness, peace and liberation from patriarchal discrimination. I agree with Nyac, if trans politics challenged the gender binary rather than reinforcing it, that would be a powerful thing. But I'm not about to tell trans people what to do - I don't have any idea what their lived experience is.
I think it is utterly Orwellian that the concrete physical biological definition of what a woman is is being twisted and redefined as something existential.