Who says Calvinistic churches are not also loaded with false converts, people who put their faith in the knowledge they have about Christ without truly knowing Him?
We can't make that determination, except by virtue of their fruit and then only insofar as it is our responsibility. Are you Lutheran? No. So what business is it of yours? Reach the lost (people), leave the denominational differences alone.
Some Reformed churches are perhaps loaded with people that lack a relationship with Jesus, but these are in the minority.