When I say I'm a feminist, I mean I believe in the equality of men and women. To be specific, I'm a sex-positive liberal third wave feminist. I am not a radical feminist, even though I am radical in some ways, and I'm not a second-wave feminist. I'm not a formal equality feminist, I'm not a dominance theory feminist, and I'm not a relational feminist. All those different group have things that differentiate them from each other, and are not quite what I am. A lot of critiques of feminism seem to pick and choose bits from each different branch-- and since the branches wildly disagree on a lot of things, they end up painting feminism as a whole as being internally inconsistent and poorly structured.
The thing is, there are different groups that exist under the name feminism, and these individual groups are internally consistent even when they disagree with each other. Just put a dominance theory feminist in a room with a sex-positive feminist. Other than agreeing that women deserve rights, responsibilities, and to be treated as humans, they won't agree on much else. Some feminists think that women can never truly consent to sex with a man; others think that a life as a housewife who has sex with her husband every day is no more nor no less to be desired than a life as a single surgeon, or a lesbian artist in a cooperative living group. Some feminists are essentialists, who think that all women have X characteristic, and all men Y; some think that men and women are fundamentally the same except for societal socialization. Some focus on intersectionality and examining queer women and women of color while others stick to the stereotypical American woman who always seems to end up white and middle class.
Feminism is, fundamentally, the idea that women are people too. Feminism sees problems in the fabric of society and a historical mistreatment of women. Do not assume that just because you have read the works of MacKinnon or Dworkin that I, or any other feminist, must be like them. Listen to people when they tell you what they believe-- it leads to a richer conversation than assuming you know their beliefs and ignoring what they say in favor of continuing with your earlier prejudices.