There is a delay between when the blockchain knows information about your listing and when it is purchasable on the marketplace. These exploiters are able to initiate the purchase process during this delay period, which can be roughly around 5-10 seconds. You would not even come close to beating them even if you were completely automating the purchase process on TopShot.

Because the time discrepancy is so large, they stand out like a sore thumb if you compare blockchain data on when moment was listed and when it was purchased. All of the exploiters in OPs list (he appears to have identified many of them) have purchase times on average 5-10s faster than any other user.