It’s not, in lieu of a complete accounting report. We don’t know what goes on to support those umpires. Are they housed? Fed & watered? Access to medical while employed? Laundry? Uniforms provided? All those things are important; furthermore, they’re overlooked variables when we start comparing these… “Destination Events” against travel, tournament, and local leagues. Tournament umpires get lured in by $75-$100 game fees, but then have to pay for their own housing, food, laundry, etc. So “to soften the dent”, assigners will put guys onto 4-6, 7 games per day!
The registration fee is because there is a lack of a vetting umpire organization / association in that region Another factor is that the entity hosting the PerfectGame -brand is anticipating either a skeleton crew of support staff (TD assistants, field marshals, etc), or they’ve been burned before on umpires leaving / forfeiting games.
Adjacent to that, PerfectGame is very cognizant and protective of their brand; as such, they’re trying to dissuade (or prevent) umpires from invariably wearing sub-par, sub-optimal, or competing-entity uniforms. Ideally, those uniform items should be provided; however, if anything is provided, there will be umpires who will abuse that generosity. Purchase of those items compels umpires to take care of them, to an extent. Of course, PerfectGame’s brand gets affected, later, when those same umpires invariably wear those uniform items on rival events (“Buh! I paid for these! Buh!”).