20 scout, I'd try telling them you have a booth that shows the way one can utilize more of what everyone shoots.
Processing and tan the hides for example.
Something along those lines, tilt your description to something that he would be more likely to OK.
Going to the event and doing some recon on whats there and what he allows might help.
Also talking attendees and vendors, asking if they'd be interested in your stuff.
Doing a end around on him to see if you could get support to change his mind.
Might also be helpful to know why he told you no. Is it just him that he doesn't like trappers?
Good suggestions DD . . and I'm guessing he just doesn't like trappers.
Big sport shows are becoming more diluted IMO, from what I've seen in the midwest. Common now to see vendors that have nothing to sell in the way of hunting, fishing, and/or trapping gear. Set up fee for a 10x10 spot can start at $750 and go up from there. I played that game for awhile and did very well, but again . . things have changed.
So I'm surprised when I see someone getting denied to set up at a gun/knife show that might have folks returning home, sharing stories of what they've seen, which might encourage others to attend that probably wouldn't have.
Maybe next time start with describing your booth as having guns and knives (you could scare up a few of these somewhere) and a historical look at westward expansion into the west . . .