Do you think I got screwed, or is it just part of the hobby?

Since you was given a shortblock I think that is what you should return.
pull the engine and begin to disassemble from the bottom up take pictures of each step donot undo any thing they did feel the rods for slop.Check cam drive,dist and oil pump drive for slop. remove topend check for slop and stem seals,This could be the cause of oil consumption. Check lifters, label them as to cylinder and I or E .
When you get to this point, with the shorthlock still assembled I would take it to the shop for them to disassemble in your presance. If they are as reputable as the shops I use there would be no objections to you watching the disassembly.
Things to watch for. Discoloration on rods;Babbit loss on bearings;Crank discoloration and rough.Ring fit in pistons.Ring markings on top of ring.
Cylinder wall problems.Rod markings.and piston marking should have been checked before final engine assembly.
I hope you used a good shop.
Roscoe