Faced with these question, some have been so persuaded by this empirical approach and so dissuaded from the helpfulness of any ideal description that they've concluded (as one probably should if Christianity is only what Christianity does) that Christianity itself isn't helpful, even being fully aware of certain idea descriptions of what Christianity actually is (I am thinking, for example, of one blogger friend of mine at Hackman's Musings who seems to have gone this route at least to some degree). We should take this option seriously, as this is not a decision of ignorance but is, indeed, an informed decision. However, we should be clear that it is a decision to give normative preference to the empirical over the "ideal" and is, at that, a decision or persuasion to conflate the ontological with the epistemological. I am of the persuasion that ontology (what is) is bigger than epistemology (what I can know and experience). In other words, I think that there is reality and significance to things with which my capacity as a human agent is incapable of keeping up, even in the case of Christianity (here, I am trying to think along the lines of Andrew Root's "critical realism" as described in his Christopraxis). In other words, while it cannot be denied that, to some degree, Christianity is as Christianity does on a empirical level, I don't think that negates the necessity or productivity of describing what Christianity actually is or should be. Indeed, I believe that distinguishing between true and real can actually help us transform the real, the lived, toward the trajectory of the true. Therefore, while there is much for Christianity to be embarrassed about, that which is given normative preference is not what we have been or what we are but what we are becoming.
Douglas John Hall begins his theology of the cross (The Cross in Our Context) by taking up a concern for this quandary between being and doing. It will not be a waste to quote him at length here.
A Christian theologian recollecting the words of the one who said "by their fruits ye shall know them" will not dismiss Krauthammer's empirical approach [which essentially submits that religion is as religion does]. Neither will he or she find it satisfactory, for it assumes, in effect, that the content of belief as such is peripheral if not irrelevant--"the essence of an abstraction"--that what matters is not the theological and ethical substance of a religion but the actions of its avowed adherents. That airy abstraction, rationalization, and hypocrisy exist--about, even!--among the religious; that gross discrepancies can be found in every faith between thought and act, what is desired and what is done: these can be readily admitted. But such an admission does not obviate the fact that there are definite consequences of belief, as of disbelief. Nor does it rule out the necessity, in every religious faith, of distinguishing between authentic and inauthentic expressions of that faith.... it is of course pretentious in the extreme when the doctrinal guardians of a religion claim to define for good and all the "real" Christianity/Judaism/Islam/etc., but a religious community must always be busy with sifting its essence from historical accidents and extraneous associations... (The Cross in Our Context, 2-3)Hall's argument continues on to support the need for a prophetic theological voice within religious faith (as well as with any system of thought which threatens to become totalizing or "triumphalistic") without such a need negating the importance of said religious faith. Theology, as such, remains important--fundamental, even!--for, as Hall puts it, "for both durability and profundity, change must be undertaken at the level of the faith that informs and sustains the act--that is to say, at the level of theology" (5). So while empirically it may seem easier, if not necessary, to simply reject Christianity as a religion that does and causes bad things, I believe that at the level of theology, Christianity cuts more deeply into ontological significance than any perspective driven epistemologically by normative preference for the empirical, and as such, Christianity has the normative force to call human action into authentic participation with that which reality is becoming. True Christianity will conform and convert the real.
Therefore, it's important for us to continue insisting, despite the violence of Christian religion, that Christianity is an invitation to peace. It's important for us to continue insisting, from biblical grounds, on the full and just inclusion of the LGBTQ community into ecclesial and social life, despite the fact that the bible has been exploited to provide the most dominant rational for their oppression in the U.S. Though we should never ignore the realities of the actions of Christianity, and at some level admit that they are what Christianity is, we do not need to retreat from naming what is authentic and fraudulent in regards to what corresponds to God's action. Because, in the end and according to the theology which constitutes the distinct character of Christian theology (i.e. the theologia crucis and its corresponding eschatological hope), it is God's action which has definitive quality and authority over reality, not ours.