I'll contain my powerlevel as best I can, but it's because they did it on purpose. A conscious decision was made at the programming level to exclude that event.
I have no concrete evidence of it but a lot of conventions post covid have implemented policies that outright ban military cosplay, equipment or any form of reenactment in order to make their conventions more "friendly" towards the current generation of furries who overwhelming reject anything related to the professionally armed world.
FWA has these policies in place. Although they are meaningless because of things like LEOSA, authority retention of LE officials, and certain military uniforms being authorized for "appropriate leave and liberty" for service members.
I won't lament greatly about the fandom perpetually being 21 years old and getting more and more progressive but its clear that people who belong to a lethal profession and have overlap in the fandom are excluded or given the cold shoulder, although it is rarely openly done. At least, not yet. I don't know how many other furry lolcows have outright said it other than Sparx but to the fandom the military is now on par with or being a "double" fed.
I think that the convention rejected the panel on purpose and when they couldn't fill the slot or the optics turned bad enough they reneged. But I agree with
@Barry Williams I will opt to not hold the panel period.