We Christians are called to use our time in this world to bring the gospel to others. We do this by talk and by example. It is possible yet doubtful that any Christian find a calling to bring the gospel to gamblers while participating in gambling. Although Christian's are free from the law we are also required to avoid causing our brother to stumble. A Christian using gambling as a means of earning support is bound to lead others into bondage by getting addicted to gambling. So, yes there is plenty wrong for Christians counting cards.
I didn't say gambling should be a priority in someones life, but if someone enjoys gambling recreationally and is able to discipline oneself then it is not a problem. Just because someone gambles that does not mean someone encourages others to become addicted to gambling.
People should do good works, but they should also have fun and enjoy themselves.