You are certainly within your right to be mad/upset. However, I would slightly disagree with your accusations towards Hornady. Hornady, like all the major ammunition and component makers, is playing catch up from the COVID days and there is a lot of demand and hoarding going on. I believe they are also recovering from a fire/explosion at their factory that killed some employees.
Buying loaded ammo, in order to obtain brass for reloading, isn't that outrageous of a proposition for the 375 Ruger. Brass for the 375 Ruger runs about $1 per case (375 H&H is $1.40/case and 416 Rigby is $3/case). A quality bullet is $1 or more. Loaded ammo for the 375 Ruger can be had for a little over $3 per round. Very reasonably priced ammunition when you compare it to many of the old line, classic calibers. BTW, Swift does produce 375 Ruger ammo with a 300 gr A-Frame bullet, as I have a few boxes of it.
Go buy 2-3 boxes of ammo and enjoy shooting it at the range or hunting. Then you will have some nice, once shot, fire formed brass for your rifle. Of course now you will have to source some magnum primers and that's not an easy or cheap proposition these days either.