You're reading that the wrong way, or I didn't articulate it well. I didn't say it only decreases the risk by 0.01%, I'm saying that I would only be 0.01% safer for paying more than twice the money. There are things you have to consider here...
1) The overall sick population of fish is a relatively small percentage of the fish in the hobby
2) Reputable places like BlueZoo, LiveAquaria, etc. Look at their fish daily and pull sick ones out for treatment, further reducing the population of sick fish
3) The percentage of sick fish that make it to a customer's door and are not already DOA is even smaller
I feel reasonably confident that I could order 1,000 fish from places like LiveAquaria and BlueZoo and only ever get 1 sick fish, time may prove me wrong, but I'm somewhere around 300 with no illness yet. 1:1000 is 99.9% safe, so even if Strikers is 1:10,000, I'm spending ridiculous amounts of money on getting a 0.01% gain in safety, from 99.9% to 99.99%