That is marketed as a UTV specific tire (besides for what is says on the BFG website, when is the last time you saw a light truck running 14" rims???).
In any case, I think even 20 psi is pretty high for off-road driving. I usually run 10 psi max in my tires that are the same size for normal trail riding and road riding, and bump down to 7-8 psi on hardcore trails. My recommendation would be to go ride a section of trail at 20 psi, lower the pressure to 15 and ride over it again, and then maybe go down to 10 and try it again to see the difference. Just this weekend a buddy was trying out his new 32's that had 16 psi in them. After a couple hours on the trail we dropped them down to 8 psi and it make a big difference in the ride, and there was hardly any "bulge" in the tire at that pressure.