‘Judaism’, defined in halacha, can be said to consist of the accepted 13 ikkarim of the rambam. The gemara says that one who denies one word of the torah, is the same as if he denied the entire torah – the torah is one, single unit. While in practice, every mitzvah is independent, the acceptance of the torah is not. These are very clear halachos in the rambam in hilchos yesodei torah – people should learn them before defining Judaism.
What the reform believe in has absolutely no bearing on Judaism. They do not believe in a g-d who commanded us to do anything(besides maybe secular social justice). Whatever they are doing, therefore, is not a ‘mitzvah’, or commandment at all, but rather a gesture of their spiritual fancies. Meaning, if a goy puts on a pair of tefilin because he likes the way they look or make him feel, that is the same reward a reform jew gets for doing it because it’s ‘spiritual’ or whatever. A mitzvah means there is a commander.
A jew who subscribes to reform Judaism believes in fewer core beliefs of Judaism than CHRISTIANS.
Christians believe in the Bible as being 100% true, without one word being untrue. They believe that G-d created and runs the world. They believe that he rewards and punishes people who do bad. They believe in the coming of(the wrong) messiah.
Lutheran Christianity’s ideas of Jesus just being a prophet, are not even forbidden for non-jews to believe. Non-jews though, are commanded to believe in the Bible(rambam, ben noach must do mitzvos because they were commanded by G-d to the Jews and them, and not because he decides that they are the will of G-d alone).
Reform and Conservative Judaism, as per their mainstream statements, do not believe in the divinity of the Torah at all, nor do they believe in the coming of Moshiach, divine punishment, olam haba, g-d running the world(see harold kushner’s ‘why bad things happen to good people’, a mainstay of Conservatism, to see this) nor do they accept the events of the Torah occurred.
The Ran writes that the entire mitzvah of emunah is to believe that G-d took us out of mitzrayim. Christians believe that, reform do not.
The fact that our feminist(itself a form of heresy and denial of the authority of rabbis{not ‘Rabbits’}) sees some sort of Judaism in reform or conservative, is very revealing of how far from Judaism the movement of ‘orthodox feminism’ is from the Torah.