OK, let's move this toward a meaningful conclusion. This shouldn't just be a rhetorical battle, and this is threatening to regress into repetitive re-explanations of beliefs. Let's fix that:
With the positive/negative rights stuff, I was meaning to delve deeper than before. I understand what your position on RIC is; I just don't think it's philosophically compelling. I'm asking a more fundamental question than is answered by re-stating your personal history with circumcision. Unless your entire philosophical framework on autonomy boils down to your position on circumcision (which I doubt), it's a much more generalized question, and you're fusing in contextual specifics that don't really apply to most situations -- even when it comes to circumcision.
So, I don't want to come across as a bully (I'm not), but I want to be direct. I'm going to ask a few questions and then explain to you, in formal philosophical terms, why I think your position is not evil or sadistic but very, very wrong. I want to explain why I'm not willing to accept this "to each parent his own" as a moral excuse for RIC.
First, I want to rephrase the crux of your argument (suspending debates over empirics.) Let me know if it's in any way inaccurate or incomplete. Here it is:
You don't think circumcision is inherently superior, or inferior, but do think parents have the right to exercise their parents on their children -- even if it results in a reduction of autonomy -- and personally feel that you will. This belief is based on the assumption that there is no objective disadvantage to circumcision, and that personal preferences have no intrinsic value. This is how you define an irrational preference.
Those who have personal preferences, and assert a negative right that impedes the positive right of enforcing one's own preference on their kid via medical proxy, should be treated as psychologically disordered, because they want something they can't have that isn't objectively superior (i.e., their preference is irrational.) Increasing the number of "disordered" people is not a valid reason to avoid RIC, because the preferences of the "disordered" should be ignored as irrational. You reject the utilitarian argument that you should minimize the number of people affected by "irrational' preferences, because you take that as an invalid assertion of a negative right based on an irrational preference.
Accordingly, there is no objectively right answer to RIC, and you reject any impediment (even questioning) of a parents' choice on circumcision, but you plan to use your positive rights by preemptively circumcising your son.
Tell me what you think. The only other thing I need to explain my fundamental objections is an answer to this question: What would make something so objectively harmful as to make exercise of parental rights harmful? Please be as explicit on the requirements as possible; examples might result in us talking past each other. (You're alluded to popularity, tradition, mutilation, etc., but we don't have a specific standard.)
Once I've pinned down where you're at on the fundamentals, I can explain where I'm at, and demonstrate why even though it is a fairly marginal bioethical issue, I find RIC to be a completely indefensible practice.