What is the problem here? It is man’s attitude to goodness, towards the blameless. So unsavoury are the righteous, the blameless, to the wicked that their very presence eats away at them, and they cannot bear to be in the same world as them.
‘But the just seek their soul.’ In spite of the frequent use of this phrase to indicate intent to take life, the subject of the second part of the proverb is ‘the just’. To translate, ‘As for the upright, they [the bloodthirsty] seek his soul’ ignores the singular possessive adjective attached to soul, ‘his soul’, while the word ‘upright’ is plural. Nor can ‘his’ refer to ‘the bloodthirsty’ as if the upright seek revenge, for ‘the bloodthirsty’ too are plural. It is more natural to relate ‘his soul’ to the singular object in the first half of the verse – ‘the blameless’ – and to make the sense positive.