One of the great aspects of ultimate is a concept called Spirit of the Game (SotG). There is a continual internal debate on what spirit means, and it's impact on the growth of the sport at the grassroots and olympic level.
Straight from USA Ultimate:
"Spirit of the Game. Ultimate relies upon a spirit of sportsmanship that places the responsibility for fair play on the player. Highly competitive play is encouraged, but never at the expense of mutual respect among competitors, adherence to the agreed upon rules, or the basic joy of play. Protection of these vital elements serves to eliminate unsportsmanlike conduct from the Ultimate field. Such actions as taunting opposing players, dangerous aggression, belligerent intimidation, intentional infractions, or other 'win-at-all-costs' behavior are contrary to the Spirit of the Game and must be avoided by all players."
Fairly simple & nice.
Simpler & nicer: we're all playing to win so don't be a jerk.
So where's the debate?
Different views of the game.
At the low end of spirit is everyone having fun. This end is the hippie end that also encourage cheers at the end of the game. Cheers were common when I first started playing. After the game the teams traded songs, parodies, haiku, limrics, etc. Sometimes fruit, bagels, or beers were exchanged also. One of my fondest memories is my "Chia Earth Champions" team belting out "Puttin up a Prayer" a parody that was well adapted by Mike Yanchak.
This view loves playing in bare feet and letting the game go with few travel calls & everyone having fun and secondarily playing hard. Soft marks on new players, teaching the game while playing; minimal heckling, etc. These viewers tend to view the potential of referees as stabbing the heart of the game.
The high view focused more on respect.
It is to promote respect for the players on your team and the other team. No problem playing with full intesity upto and within the bounds of the rules. That's how I show respect to my opponent is by training hard & playing them hard.
This view can be offputting to new players but it's completely within the established rules; get over it. You moved your foot while throwing, you travelled. My hand was stationary when you threw the disc & hit me, you fouled me - it doesn't matter that my fellow defender was juked out of his socks. These viewers usually like the referee concept; often because the other player is just a jerk.
Tied to the SotG debate is if the game at high levels should have referees. Currently there are Observers who make line calls and if requested can enter a "foul & contest" call and issue an overrule. The referee debate is if all the calls should move a level of an independent observer. The idea is this will speed game play, neutralize ticky-tacky teams & players, and bring legitimacy to the sport to outside spectators. The downside is clearly losing integrity. I show respect for the other player by knowing the rules and adhering to them. If I foul someone it is a "no-contest"; if the contact was incidental, I don't make a foul call. Respect, for the game and the teams on the field. R-e-s-p-e-c-t find out what it means to me = Integrity.
Most other sports get into seeing how much you can get away with before a ref makes a call, or the other end of a ref costing you the game with a blown call.
Referees are administrators of justice. As is expected people want mercy for their side & justice against the other side.
Ultimate is neat for having SotG and it has been preserved very well over it's history. It has a simple process for raising issues ("foul") and accepting or rebutting said calls ("contest, or no-contest"). This works for 95% of the time until the lack of knowledge of the rules shows up and especially when it gets coupled with the lawyer player.
Basically the game parallels life in that justice works best when the law is known & the lawyers are out of the way.