As an IP attorney in the US, it's hilarious how many of you are commenting as if you have even the slightest grasp on trademark law or how the USPTO works. The YETI application was refused because the HC is seeking to register the mark for clothing and other merch-related items for which there are already registered YETI marks. It's not because the government thinks people would be confused between YETI being used for the provision of hockey exhibitions and YETI being used for coolers and insulated cups.
When the YETI name was first floated, there were several articles pointing out that it would be a difficult path to register the YETI mark because of the existing registrations, which the HC was aware of. The HC is free to try to negotiate consent or coexistence agreements with the owners of the existing YETI registrations (which I'm sure they have tried), but it appears those holders of the existing regs aren't willing to play ball (or puck). Trust me--both the NHL and the USPTO have very smart attorneys handling these matters.