The women-only classes around my way are things like car/house maintenance (mixed classes are available), or for women new to the country (there are also mixed groups, and male-only groups for this). My gym has a women's section. I should mention I'm in a self-id country, so actually these are all mixed sex spaces in practise.
The reasons are that it's been shown that in a mixed class, men (and boys) talk over women and dominate. Therefore, for the comfort of women, and so they have more of a chance to ask questions and learn, there are some women only classes - generally in the more traditionally male area where women might lack confidence.
I doubt I need to explain why some immigrant women might want separate classes (obviously depending on the culture they came from), and why it's good to be able to talk to, and educate some women on their rights without male relatives around listening.
Has feminism changed to mean hating men and not wanting to spend any time in their company?
What a ridiculous thing to say. I spend most of my time in the company of boys and men who I love very much, or who are strangers or colleagues sharing public space. Doesn't mean that I should be forced to share with men in every space. Feminism, as ever, is about liberating women. Sometimes, it's only possible, or better, or just more comfortable, to do that with men not around.
Doesn't mean we hate men.
I don't want my son following me into the toilet while I do a poo. Doesn't mean I hate him.