Why does forgiveness come with a price? I thought the Christian god was supposed to be merciful? It's not mercy if I threaten to kill you for wearing cotton-polyester underwear, and only relent if you become my slave for all eternity: that's extortion.
Compare that with human systems of justice. In places that don't have the death penalty, some murderers who have served their time, and are deemed not to be a threat to society, can be released. There is no condition attached in the form of "you must now be a slave to the judge for the rest of your life". No- you are now able to re-enter society, and live your life. God shows no such leniency. On earth, you're not forgiven unless you obey, and in hell, you face punishment for all eternity. God's murderous rage and implacable authoritarianism do not, for me, constitute a sound moral code. You want an obstacle to belief? This is one of them.