One fact is inescapable in the study of religions; it is that different religions make competing and incompatible claims about the nature of reality. One cannot believe all the things that all religions teach without self-contradiction. Some people find this to be an enormous stumbling block. Having decided that one religion is "true," they are reluctant to look at other religions except as examples of flawed, inaccurate, or even sinful thinking and practice.
Claiming the unique truth of one's religious traditions (or even one's personal religious beliefs) is known as a confessional or believer's perspective. Such a perspective is not incompatible with learning about other religions. Whatever one may think about the value of other religions, one can study them as an exercise in cross cultural understanding. Applying this same openness to the study of one's own tradition can reveal it in a new light without undermining belief in commitment to that tradition.