I don't think he cares at this point. It's a better sell and a better PR approach to support the overall economy as opposed to standing up for a relatively small group (the IPA) that make FAR more than the average American worker. Most people would have very little sympathy for the UPS pilots.
UPS captains earn a minimum $255,128 a year, and often take home about $35,000 more. By comparison, the next highest-paid captains at FedEx make $230,379 as a guarantee.
The average pay for all UPS pilots, including captains and first officers, is $238,000, and they also have a benefits packages with two company-funded retirement plans in addition to a traditional 401K and pension. Union members receive health insurance that costs them a third less than what a typical U.S. family, with far lower income, pays.
In an election year, it's all about who can get the most people, and money, on their side and there's more to lose and less to gain in supporting what would be spun and perceived as "supporting the rich 1% crowd."