Guess I am confused as to why a piece of metal from the company he bought the hubs from whos guard is designed specifically for said hub isn't good enough, yet some other companies piece of metal would be better.
Like I said, maybe he wants more options. I have the BSD front/Cult rear. Does that mean I have to buy the specific guards to them the company makes because clearly that is the ideal choice?
No. It means they make a guard for their hubs for other reasons like so you can support their company, or so you can get a hub guard that will 100% fit the hub. That doesn't mean another guard out there won't be better though, or maybe have a better design. For instance, the Cult Match guard fits the Cult Match hub perfectly, but seizes to the axle very quickly due to its design. The Knight hub guard also fits it perfectly, and doesn't seize. Therefore that would be a better choice.