Quick (and correct) guess was that the hotel is unionized:
http://www.foundsf.org/index.php?title=Hotel_workers_got_it_right
which means that conference organizers are not allowed to bring in their own coffee and likely requires a minimum number of worker hours per pot served.
In my office I used to buy beers and snacks for the team on occasional Friday afternoons. I’d send a couple guys to the grocery store with $50 or $60 and we’d have plenty left over and we did our own cleanup in 5 minutes. The landlord caught up with me and informed me that was a violation of the (union) catering contract which requires two people to set up, someone to serve and a two-person cleanup crew. Total cost would be over $500, which would have worked out to about $20 per can of beer, about the same as the cup of coffee in this article.
Unions were created to ensure fair pay and treatment for the workers doing work that employers needed them to do, not demanding to do jobs that don’t need doing.
Unions had a place years ago - - today they’re part of the liberal rip-off of workers.