Actually, there is nothing wrong with actual social justice.
However, social justice as it has been taught is, as you say, not following either the teaching of Christ or the teaching authority of the Magesterium of the Church.
What too many in the Church have taught for the past 60 years or so is half the doctrine...which makes it no doctrine at all. They (mis-)teach the principles of the common good and solidarity yet leave out subsidiarity and participation. Consequently, rather than teaching the authentic social doctrine as taught by the Holy Fathers since the days of Pio Nono, they end up teaching socialism.
Authentic social justice is achieved when those who have plenty voluntarily share with those who have need and when those who receive the benefits of that giving receive it with gratitude. The ersatz social (in)justice happens when governments act as Robin Hoods, taking from those who may or may not have plenty and turn it over to those who may or may not have need. Those who have their goods stripped of them feel as if they are victims of larceny; those who receive those goods feel entitled and feel entitled to ever more. Neither receive any type of spiritual good from this and, in fact, my belief is that those who are the recipients actually are damaged in the process.
The key word is "voluntarily" This makes it charity. By lobbying the government to redistribute the wealth, the current crop of Catholic bishops has endorsed theft, not charity.
I agree. This process turns what otherwise might be decent people into misers who hate their neighbors, and it dehumanizes the recipients. How many times have we seen posts in which someone claims that it's just to treat the poor as if they were house pets, simply because "they're taking my money"?