I disagree with your assertion that what makes a human is the rational, thinking being. Certainly, that is a part of what we are, but if that were all we were, then we’re really nothing different than biological computers. Now, of course, one could make the argument that that’s all we really are, but I think that our more primitive drives and urges are part of what shape the human experience. That is, I think what makes a human is an aim to find the proper balance between our base instincts and our rational minds.
I can go through life thoroughly indulging my base instincts, and I’m likely an utter failure, on a personal and social level. On the other hand, if I stick to only my rational mind, I may be able to be a contributing member of society, but I miss out the parts of life that make it worth living. In fact, as a human, finding a proper balance between these can make it so we can potentially excel even more at both. So, for instance, I can work hard at my job and make sure I eat healthy and get exercise, but it’s also important to have vacations, have pleasurable experiences, seek out friends and other relationships.
We shouldn’t make choices just to fly in the face of our baser instincts but, instead, we should rationally decide the costs and the benefits associated with them. Yes, it’s a bad idea to blow my savings on an expensive sports car when I would be better off using it toward paying off debts or buying a home. But why would it make sense to deliberately make myself cold just as an FU to my id? Besides, a lot of the deeper desires we have have some basis in reason, as they evolved to be our instincts for a reason. The question is whether those reasons still make sense in a modern world or toward furthering other goals I’ve consciously set.
My goal, in general, is to make sure I’m not just giving in to my more base desires, but to decide if it actually makes sense for me. For instance, in general, we have a biological urge to procreate. So, do I really want kids, or would that just be me giving in to that biological urge. Or, if I have a goal of competing in a marathon, maybe I will pass on a piece of cake, if not, maybe a small treat is worth it.
In short, this seems like taking an extreme approach to controlling one’s urges. It’s like, sure, one person might over-indulge in alcohol and become a drunk, so to avoid that someone else decides never to have a drop. Why can’t a reasonable person have a nice glass of wine with a good meal or share a beer with a friend from time to time? It’s not a one or the other, it’s a false dichotomoy, and I think the idea of ego over id is a similar situation.