Soak meat in water to get rid of smell?
They may be using beef round, precut stew meat almost always is, unless otherwise marked. 
It has a livery taste and odor some people find objectionable.
Generally the more work a muscle does the better it tastes, the round comes from the rear leg and rump, the least exercised muscles of a cow.
Probably has nothing to do with the blood, but hopefully someone can enlighten us to exactly where the funk comes from.