LRD - yes I think feminists analyse patriarchy as being the root issue in women's rights. With patriarchy being simply defined as male dominated society. Patriarchy is just a system of social organisation.
I agree with you that a woman does not need to write a book to be a feminist. A woman does not need to write a book to be a brilliant thinker, to participate in and forward the movement or to contribute ideas to it.
Feminism is a grass roots movement that belongs to all women and girls, regardless of whether they can read and write books or not.
And, yes the internet has brought a lot to feminism as it allows women to exchange and share ideas, and to reach out to each other and organise. I'm not knocking that, I think it is ace.
I'm simply saying that feminism has a long and rich history and that it has been a long time in the making. And, that like most political movements, it has a written history. As you say, women's history has been censored/unpublished and much of it has been lost (writers such as Dworkin and Millet are out of print nowadays - which is awful). So much of feminist thinking never made it into writing at all, thanks to male dominated society.
However, feminist analysis does exist as very high quality written work of importance and influence and I take issue with people dismissing feminist analysis as something they have read on the internet when I doubt they have read any of the works that are considered important to the movement and its history, without which current feminist writing on the internet would probably not exist at the consciousness raised level it does.
I absolutely disagree with 'intellectualising' feminism, but I equally think it is a shame that relatively few women read the works of our foresisters. Especially as the vast majority of written feminism is intentionally accessible and is easily understood as it is about US, WOMEN and OUR lives and lived experience. We get it.
It is pretty amazing that thinkers such as Dworkin and Millet got published in the first place, and I'm not sure that they would now actually. All the more reason to read them...