Other companies love UPS management. If you want to stay a decent person, take the job for a few years and move on.
I've only ever seen three types of supervisors:
1) Good guys who get beat down trying to do right by everyone, who leave for greener pastures with some emotional/mental scarring proportional to their time at UPS.
2) Good guys who get beat down trying to do right by everyone, who don't leave for greener pastures. They are depressed, get fat, hate every part of the job, but are still too nice to upset their superiors or their hourlies. And they're too scared to pull the trigger and leave the company. Their lives SUCK.
3) Guys who assimilate and embrace the dark side.
Do a few years, save some money for your transition away, don't worry about the numbers except enough to keep your job, and use the experience to get a great job somewhere else. Of all management people I know, those are the ones who were happiest. UPS will not share much information with new companies you apply to. That means all their yelling or disappointment with you will not reflect on your record or stop a new company from hiring you. All they will report is your position and hire/end dates. You can spin your employment and success at UPS any way you want.