1) Religious commandments were given to such of those set of people who had to be guided at the right path at that point of time. Instilling fear is one of the tactics to put them on the right course.
2) The value and purport of some commandments have an universal significance. They, if followed, will lead to long term peace and happiness. These 3 commandments fit into that category.
3) All religions acknowledge the imperfectness of man but guide people towards achieving perfectness.
4) These commandments are to be taken as goals to be achieved in life; any slips in them are worth repenting; any deviations are worth course-correction. Prayer and seeking forgiveness are established practices in Christianity. Mercy is considered one of God's greatest qualities. Don't Christians repeatedly say that Jesus Christ's blood saves our sins?
5) This said, we should also re-look into the fact in (1) that some commandments are people and time-specific. 10-commandment shuns idolatry, whereas in Hinduism, idol worship is very much accepted. There are countless Hindu saints who started off with idol worship and evolved to become great spiritual masters.