How come the logic we use to justify circumcision doesn't seem to apply to anything else?

You mean "because most doctors think it's a pretty good idea?" Yeah, that logic isn't ever extended to anything. Brushing teeth, regularly bathing, washing your hands before you eat, getting chemotherapy when you have cancer...

Also, the word you're looking for is hypocrisy, or hypocrisies if plural.

infant circumcision is totally irrational - women mutilate their sons because of sexual objectification, pure and simple, it has nothing to do with logic

You posted this question twice. I think you did the update on the other version.

I didn't realize you asked this question twice. Since the answers here are wanting I'll answer again:

1. There are Latin families that pierce the ears of their baby girls, usually as a physical display of their femininity.

2. Women get breast enhancements or reductions for aesthetic and sometimes for health reasons (large breasts give back problems, reduce some quality of life).

3. We clip our finger and toe nails for sanitary, health and functionary reasons.

4. We cut our hair for sanitary, health, functionary and aesthetic reasons.

5. Some men and baby boys undergo in-patient, locally anesthetized surgeries to correct urological disorders. It can be argued that an uncircumcised penis can present a urological disorder.

6. People get piercings and tattoos all over their bodies all of the time.

7. Surgery of any kind that enhances some quality of life.

And something else that makes this list truly similar to circumcision is that none of them causes any harm to the individual.

You mean like removing wisdom teeth before they become a problem? Oh, wait. We often do that.

Also this is often a religious ceremony. If your religion doesn't recommend you do this, don't have it done to yourself or your children, but don't pretend, under the guise of freedom and human rights, that people can't practice their own religion, even if it involves a procedure that makes you squeamish.

Another penis?

How is that illogical?

Oh, wait, your logic is flawed.

The Jews invented circumcision, so ...