That has nothing to do with men classifying sin to make themselves feel better about themselves.
When are you going to pluck out your eye(s) and cut off your hand(s)?
Get back to me when you take the words of Jesus seriously.
JESUS classifies sins as mortal and venial.
I.e., Jesus talks about sins that cause people to be damned, AND Jesus talks about sins that people can commit, but which do NOT cut them off from "the kingdom of Heaven."
Since JESUS taught that some sins are mortal, and some sins are venial, I will go with what Jesus taught.
Cf: http://www.catholic.com/blog/tim-staples/mortal-and-venial-sin
As you can see from the words of JESUS, your denial of the reality of mortal and venial sin contradicts what was taught by JESUS.
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What Does the Bible Have to Say?
Matt. 5:19:
Whoever then relaxes (breaks) one of the least of these commandments and teaches men so, shall be called least in the kingdom of heaven; but he who does them and teaches them shall be called great in the kingdom of heaven.
Our Lord here teaches that there are least commandments a person can break and even teach others to do so yet still remain in the kingdom of heaven. That is both a good definition of venial sin and perfectly in line with paragraph 1863 of the Catechism. Then, Jesus goes on to warn us in no uncertain terms that there are other sins that will take us to hellif we do not repent, of course. For example, in Matt. 5: 22, Jesus says, whoever says You fool! shall be liable to the hell of fire. In verses 28-29, he says:
But I say to you that everyone who looks at a woman lustfully has already committed adultery with her in his heart. If your right eye causes you to sin, pluck it out and throw it away; it is better that you lose one of your members than that your whole body be thrown into hell.
Clearly Jesus teaches there are some sins that will separate us from God for all eternity and some that will notmortal and venial sin.
http://www.catholic.com/blog/tim-staples/mortal-and-venial-sin
As you can see from the words of JESUS, your denial of the reality of mortal and venial sin contradicts what was taught by JESUS.