Excellent question. "Feminist Philosophy" as a title covers a range of types of philosophy that are united in the goal of offering a critique of patriarchy and exploring the positive contributions philosophically that are made in light of being female (in terms of both gender and sex, and in terms of the extent to which gender is a social construct, etc). I take your point about why the term "feminist philosophy" seems out of place with the nature of philosophy because the term denotes advocacy and commitment to a particular position, rather than a more open-ended inquiry into questions of gender, sex, social realities, and the like. But I suggest that the term is no less philosophical than terms like 'Marxism' or 'Marxist philosophy' or 'Kantian philosophy' and the like. Perhaps your concern is (at heart) the worry that if a person is a self-described feminist philosopher (or Marxist or Christian or Idealist ...philosopher) this suggests that the person is no longer open to alternatives. Good point. But so long as a "feminist philosopher" could (in principle) abandon most feminist theories and remain a philosopher, this suggests that such terms need not be strait-jackets.
I suggest that when a person calls or describes a gender or species or event or thing as beautiful, this implies or signals that the person believes the gender etc is worthy of aesthetic pleasure or delight. There need not be anything sexist or demeaning in this, and it does not suggest that the object of delight is merely an object of delight or that the beautiful "object" (or the object of beauty) is in some sense passive. One might claim 'the women Olympic athletes swam beautifully today' or 'the women soldiers performed beautifully in their rescue of the orphans yesterday when they met with severe resistance from the hostage-takers' without any sexism coming into play.
Going a bit further: I suspect the phrase "women are beautiful" is somewhat odd. I suppose one might first want to know the scope of the reference: are all women beautiful or the majority or a significant number of women are beautiful? Are women all beautiful in the same way? What are the reasons for thinking all or many or some women are beautiful? Are women beautiful because they are women or for some other reason? What would it be like for a person to actually take aesthetic delight in all living women (as a gender) currently on our planet? Or possibly taking pleasure in all past and future women? I suppose one is more likely to hear a more specific claim like: 'Those women who attended the conference on human rights are doing a beautiful job presenting their case for famine relief'... or something similarly more specific. Similarly, I think one needs to get more specific in order to really be guilty of sexism. Probably the following would be pretty sexist: "the only thing better than a beautiful car is a beautiful woman" or "beer tastes better when you are sharing it with a beautiful woman." I can imagine how these might be said in a non-sexist context, but they move toward sexism insofar as you are comparing a woman to a car or you suggest that if you really like a certain drink, it will enhance your enjoyment of the drink if you are flirting with a woman (woman as sex object and beer enhancer)! Put-downs of women or treating them in a sexist fashion will sometimes seriously depend on context. Imagine Hillary Clinton gives a passionate talk on human rights at the United Nations calling on Syria to stop its abuse of human rights. Imagine further that after Clinton's heated speech the Syrian ambassador rises and rather than address Clinton's admonition and call to action, he said "Your hair is beautiful today! My wife wants to use the same hair stylist. What's her number?'
Good question! First, there have almost always been women in philosophy in the west, though their status has been very difficult owing to Patriarchy. There is an excellent four volume work called A History of Women in Philosophy, published by Springe. This largely addresses what women philosophers have thought and think (the history goes up to the early 19990s) but you can also find in it pictures of how males viewed females in philosophy. The history is sad; Aristotle was bad, Plato a bit better (he thought women could be rulers in an ideal republic). For a catalogue and examination of the grim ways women have been viewed in culture and the history of ideas, you might check out Simone de Beauvoir's classic, ground breaking book The Second Sex, published in 1949. So, the Springer History will give you a good look at the classical scene, and you might also look at Genevieve Lloyd's The Man of Reason:'Male' and 'Female' in Western Philosophy, published in 1984. For two early modern works arguing for a greater role for women, you might check out Mary Wollstonecraft's A Vindication of the Rights of Women and J.S. Mill's The Subjection of Women.
For the contemporary state of play on women in philosophy (and addressing questions of how women are viewed in the world of philosophy), you might check out the online website of The Society of Women in Philosophy:
This will have abundant resources and links that will allow further inquiry.
To expand a little on Charles' answer, some theorists draw careful distinctions between "ethics of care," "feminine ethics" and "feminist ethics." An ethics of care is one in which the locus of moral goodness is in relationship; as such its emphasis is on particular, embodied individuals in concrete, historically-situated patterns of interaction. As Charles points out, it is generally taken to arise from Carol Gilligan's work in moral psychology (as opposed to ethical theory, and this is an important distinction also; moral psychology is descriptive -- saying how things are -- while ethical theory is normative -- saying how things ought to be). Gilligan observed that women are more likely to assign moral value to relationship, and so care ethics is often described as "feminine ethics," although it is certainly not the case that all or only females think this way. "Feminist ethics," as those who draw the distinction understand it, takes care ethics a step further, and focuses on lived relational experience characterized by oppression and marginalization, recommending ways to overcome this oppression and marginalization. Many feminist ethical theorists would say that standard ethical theories (utilitarianism, deontology, Aristotelian virtue ethics, etc.) fail to take seriously the systemic features that entrench oppression and marginalization.