Unfortunately, UPS FT management is, and has always been as I know much like a UFC fighter. On an fight interview they may praise God, Mom & the U.S.A.... however their real personality is very angry & tormented. Around Y2K as preload swept the nation and package drivers no longer loaded their own cars and 1/2 of a late start neighbor car. UPS had to hire bosses for these preloads & inside for phones, technology advancements. These PT supervisors are just kids and really don't have that UFC mentality.
You sound like a caring young lady and I believe we all know what you're saying but the culture in management at UPS is not changing. Never has as long as I know. One thing it sounds like is you don't have a lot of chips on the table to be forced to hang in there just 12 more years or whatever. So, I would recommend to use this opportunity as a leader to venture out of UPS and find another career you'd be happy in.
It's not like you're staying for the cash, right? You get what 27-hours guaranteed a week but no more, no stock, between $25-30k. You can find that about anywhere and even more...plus, a sense of pride and when you get your ass chewed you know it's not UFC people... it's a legitimate reason.
Look elsewhere. Be happy & quit screwing all the horny drivers.