Social justice gets a bad name due to its often times disconnect with doctrines of the Church. The way I am reading this post, forgiving God, is certainly an example of this disconnect although it may not be intended in the blasphemous way it could be taken. We are creatures and the Creator is all good, Goodness itself, and we have no need or even right to forgive Him.
Often though, in a sense, in regard to ones own spiritual journey, one may need to “forgive” God in order to start afresh mentally. What this is in reality is forgiving ones erroneous impression of God so as to begin a true study of God without animosity. This has nothing to do with the true God Who is Creator and Who loves us. It is purely a psychological exercise to move on afresh.
The Church has centuries of authoritative study and definitions against heretics and heresies regarding the Nature of God and this forgiveness that is indicated in the post is so wrong as to be akin to heresy. It is our job to beg forgiveness for our continued failures due to personal sin. We cannot expect any response from God as we are unworthy to receive anything but condemnation. That God offers us redemption and Grace is only due to His total Goodness and has nothing to do with our actions. This is not meant to belittle God’s Creation but is a reflection of the humility we must have and comes from the true Nature of God as revealed to us by Jesus and His Church.
True social justice is about the correct application of the doctrines and dogmas as offered to us by the Church in relation to our neighbors. Social justice is about equality in charity (Love) concerning what is owed to people and confusing this with being owed something by God or expecting a response as if we were equal with God is a work of Satan, though sadly a fruit all to often associated with what passes for “social justice” classes nowadays. The Pontifical Council For Justice And Peace published the “Compendium of the Social Doctrine of the Church” and should be the starting point for the study of Catholic social justice.
Perhaps the post wasn’t worded correctly or was read erroneously; if so please reiterate to clear up any misunderstandings on “forgiving God”.