Reality is an Absolute and so a Reality based Philosophy would be likewise.

One of the biggest criticisms of Objectivism is that it is too black and white. That is is a philosophy of absolutes and thus is dogmatic, insular, and, causes schisms between people. However, this is to not understand why the philosophy is very much indeed steeped in the black and the white. Reality itself is black and white. Something is either true or it is false. It is real or it is delusional. Is evolution true? The answer is yes or no there is no grey. Is the Big Bang a fact? Yes or no there is no in between. It is due to this that Objectivism is an absolutist in this sense form of philosophy. It is not all of philosophy, but, it is based on objective reality being real and our rational faculty being our means of survival both. 

Existence does exist and your consciousness is what is perceiving that which exists not creating it. If you agree with this you agree with a core of Objectivism as a philosophy and ultimately with the philosophy of Ayn Rand on this point. It is this outward view; this objective reality stance that makes Objectivism an absolutist philosophy in the sense that it requires accepting, and, not denying reality. Thus on matters of what is true or false in reality it relies on the absolutes of both of these concepts. This is why one can be and is totally consistent in both using Objectivisim as their philosophy; using the philosophy of Ayn Rand, but, also disagreeing viciously with her output and her application of her own philosophical methods. 

I do not want to go into another Objectivism is not Randroidism rant, but, it is not Randroidism. Objectivism is Objectivism; objective reality, reason as mankind's means of knowledge, rational self-interest and politically individual rights. This is what makes you an Objectivist and it is not agreeing dot and toddle with Ms. Rand on everything. This is also why you can be an absolutist on matters of Objectivism and also not be dogmatic, insular or cause schisms. For your outlook if you understand the philosophy is always looking outward to what evidence exists for what. Then taking your conclusions from there. Objectivism is the philosophical system discovered and named by Ayn Rand, but, it is not "whatever" Rand ever thought the application caused as an outcome. 

For example; you can truly say that sex is a good thing for mankind, but, what positions or types of partners is up to what is best for the interests of said individual person and the context of the situation at hand. Objectivism is absolutely correct on a fundamental level about the goodness of the nature of the act, but, how you apply it is up to the individual and their own contexts. Thus, Objectivism being used properly with full thought and not with hasty rationalization can indeed help you discover objective/absolute black and white truths about the matters of most importance to an individual human. The reason I am an Objectivist is because I find that the very core matches the absolute reality we call the objective reality. People might disagree with the ethics or the politics, or even the art. However, the epistemology and metaphysics is concretely true and well absolute.