That list is broken into three groups
Vendors Pulled Out (207)
businesses who were going to be exhibiting at the show who have now pulled out
Speaker / Celebrites Pulled Out (32)
people who were going to be exhibiting/speaking at the show who have now pulled out
Other Boycott Supporters (39)
people and businesses who are sympathetic to the second amendment who are letting their customers and followers know what a bunch of anti-american vermin the organizers are
I remember the massive booth Cabelas had the year that I went; seeing them on the boycott list is heartening. Even though they typically sell a massive amount of merchandise for the show, it is just considered an advertising opportunity, not something that adds to the bottom line, with an overall goal of breaking even and cleaning out the warehouse.