How is Adobe modifying a system file at all? Does Adobe run a background process with root privileges?

Yup. Just checked. Right now I have "com.adobe.acc.installer.v2" running as root on two threads. The other 3 background processes (at least those with adobe in the name) are under the user. The whole stack is using like 75mb ram at all times. You kill the process they restart. You delete the files from your launchd, open adobe software they come back.

AGMServices it's optional but gets shoe horned at install time.