all joking aside there is probably no system that is completely random- for example in this case it may well be that there is some pedigree reason why your system is profitable. as someone alluded to the sire midnight legend earlier- that may be a sire underestimated by the betting market.
also I have a theory that better horses are given better names. for example an owner or trainer may have a list of possible names and hold the better ones back for the better horses
thats the only explanation I can come to anyway