I do not think Reform or Conservative standards for conversion warrant the authority to decide who considered a Jew. At the very least a Rabbi must keeps kosher and the sabbath in order to be given authority to do so, otherwise it's no long Judaism in my opinion, but more like Jews for Jesus. However, there are some ultra orthodox who are too extreme and their decision are not based on halacha, but politics and personal bias. That is wrong. International Rabbinic Fellowship is an activist group and not a council of Rabbis, it is understandable why their authority is not accepted. Look at their website, they are politically motivated.
Israeli teen lightly wounded from stone throwing in West Bank settlement of Kiryat Arba (Haaretz)