I was surprised at that too, I'm starting at 15.
$8.50 an hour was the starting wage at UPS until April 24, 2014 with no retention bonus when the 2013 CBA was declared ratified (over the objections of many locals).
Starting wage was then bumped up to $10 an hour retroactively to Aug 1, 2013 with no make up differences for those that were here before. Those that quit in between were not paid the difference. Those that didn't quit saw a 38% tax applied to the make-up check reducing it to a couple hundred dollars.
So someone that started many, many years before you is barely making more than you do off the street--which has been a huge contention and in fact does cause hard feelings: imagine what those that have had to live through watching people off the street valued more or essentially equal to them dollar wise feel like after putting in years of blood and sweat.
So the whole I feel issues with the working environment won't get you a lot of sympathy with union members in the 9-20 years seniority department. If you are here to make as much money as you can plus use the benefits, you should stay. If you are looking for a job to hone career skills and enjoy while furthering your education---you should find a different line of work. And rest assuredly the company will take away any bonus they can as soon as they can to get new hires like you to quit as you start costing them more money in the form of benefits.