In Proverbs 6, the writer lists 7 things that God hates.
There are six things that the Lord hates, seven that are an abomination to him: haughty eyes, a lying tongue, and hands that shed innocent blood, a heart that devises wicked plans, feet that make haste to run to evil, a false witness who breathes out lies, and one who sows discord among brothers. - Proverbs 6:16-19 ESV
I don't think there is a contradiction, but it seems that there is a tension when compared to Psalm 51:5 and 58:3
Behold, I was brought forth in iniquity, and in sin did my mother conceive me. - Psalm 51:5 ESV
The wicked are estranged from the womb; they go astray from birth, speaking lies. - Psalm 58:3 ESV
Who are the innocent mentioned in the proverb if no one is innocent by the verses in the Psalms?
I also think Jesus' words could be considered here also when talking about little children.
but whoever causes one of these little ones who believe in me to sin, it would be better for him to have a great millstone fastened around his neck and to be drowned in the depth of the sea. - Matthew 18:6
Are these little children an example of the innocent?