It's a good point that you make Goatface. Omni Air don't use Brize Norton for free, their landing fees, handling charges, fuel etc will cost them as much if not more than at Newcastle, Glasgow or Dyce for example (all of which they use often during the RIPs).
SeldomFitToPost is maybe genuinely ignorant of the fact, but I guess those at the (apparently) sharp end are too important to be concerned with such trivialities while spouting guff on the internet. In his small world it's apparently free for a charter airline to use a military airfield.