system
Given the following post, respond as if you're commenting on Reddit:
human
Why don't I get an infection when I bleed from my ass?

If shit touched a cut anywhere on my body but my ass, I would be incredibly likely to get an infection.

If the tiniest bit of shit gets in my urethra I get a UTI.

Why don't I get an infection when I pop a hemorrhoid, or just rip my ass taking a ridiculously large dump?

I just realized today that all I do when I bleed from my ass is dab off the blood as painlessly as possibly (Read: Probably not very well) and my body somehow wards off a horrible blood infection. 

How?
gpt
You're assuming that your own fecal bacteria would infect you in other locations.  That's usually not true, those bacteria are "known" to your immune system and are already present in huge numbers in your body.

They're mostly docile decomposers, not aggressive pathogens like Staphylococcus that will start attacking exposed tissue.