You need to develop more ways of thinking than Thomism. At the end of deconstructing sin into parts, you need to put it together to make for "sin". There is no "objective sin" because there is nothing outside of the cognitive model--a mental construct--of bad or wrong that you are calling "objective sin". It doesn't exist. It isn't some ideal bad form out in the sky that we grab and decide that we are going to implement or not. Sin is personal and contextual. 


Thomas lived in a time and world that understood itself in terms of Christian thought, so he has the mixture of wrongs and injustices against other people identified as some version of sin...material, actual, etc. We don't live in that time--and the thought processes of scholasticism are NOT required for Catholic faith. They are not required and it is confusing and ambiguous to say that they are. Cognitive constructs, developed in the academic world and used practically as heuristic tools, do not exist outside of the mind.