This discussion feels like a rollercoaster!
I completely agree that referees can't be considered volunteers. There's a valid argument to be made that they deserve higher pay.
We all wish we were paid more for our work, but we live in a capitalist society where profit reigns supreme. Debating fairness is subjective, as fairness often depends on individual perspectives.
Having worked in public service, I've encountered many people dissatisfied with their jobs or pay. I've always believed that if you don't like the pay, work, or conditions, you should seek other opportunities.
If referees at the levels we're discussing are unhappy with their compensation, they would likely leave, prompting change from those in charge. The fact that there's no shortage of referees at this level suggests they're content with their pay.
Perhaps referees at this level aren't driven by money. Instead, they might be motivated by the challenge, the opportunity to officiate at a high level, and their passion for the sport.