^^^ This, x 2
Sizing new brass solves any handloading issues, assuming a FL die is used at least for the first loading.
Throating is always going to vary anyway depending on weight, and type of ogive. For the most precision, throats are cut independently based on an actual handloaded round provided to the smith.

It's the factory ammo which is apparently a problem (not aware of it)- no doubt sloppy/worn machining working past it's capacity keeping up with demand for the cartridge. This isn't a problem with the cartridge- it's the ammo and brass manufacturers as he says. Gotta say though, I've not heard these outcries he's referring to.