...the very best professional refs make terrible calls all the time. if your standard of 'good' vs 'bad' spirit relies on the absence of terrible calls, then no one that plays ultimate has good spirit. your standard becomes meaningless.
Professional refs may make terrible calls, but it is about bad perspective. They make bad calls because they saw something the wrong way; they go to great lengths to avoid these mistakes, but they are going to happen. The bad calls are NOT, however, due to a misunderstanding of the rules. I guarantee you that they could sit down and pass a written rules test with A+ every time because they TAKE THEIR RESPONSIBILITY SERIOUSLY.
I trained as a soccer referee for 8 years and we were constantly being evaluated, trained, tested and observed. When a bunch of us would get together for dinner at the end of a tournament, you know what we would talk about? The finer points of positioning on Corner Kicks from right footed players vs left footed players. Why? Because refs CARE and TAKE THEIR RESPONSIBILITY SERIOUSLY.
When and Ultimate player doesn't know where to set up after a pick or doesn't bother staying on sides, or contests something they shouldn't because they "don't know the rules" , I see that they do not take the heavy responsibility of Self Officiation seriously. It just blows my mind that people spend thousands of dollars a year and all their free time and don't spend the time to practice being a good referee. Read th fucking rules