Thank you for this thoughtful question.
Whilst studying Literature during my English degree, the use of critical theory to illuminate authors’ intended and, more importantly, unwitting messages was deemed good practice. I think critical theory is very useful in highlighting things about culture and society that we accept as normal, or as some post-colonial theorists term it, “common sense” ways of thinking. These “common sense” ways of thinking often result in the oppression of minoritized groups, such as the ones listed in your question, and continue to exist unquestioned and unchallenged.
For example, we generally accept “common sense” notions of 2nd and 3rd generation minority ethnic groups being “caught between two cultures” Eg. A young Asian son wanting to break free from an authoritarian father’s control or, as a film example, the plot of ‘Crazy Rich Asians’ whereby a ‘westernised’ Asian woman has to contend with the traditional culture of Singapore. Whilst on the surface, the movie presents a heart-warming story of a couple fighting to stay together, the use of post-colonial theory, for example, might reveal that there is in fact a battle of cultures going on, and whose is the best? A feminist reading of the movie may critique how the female protagonist is subject to the ‘male gaze’ and becomes an object to be made good enough for marriage.
When we apply critical theory to the church, some insightful things can be illuminated. For example, Marxist theory might be useful in helping us to analyse why and how ‘prosperity gospel’ has been so appealing in the church. Has capitalism seeped into our understanding of the gospel and is this a threat to the concept of grace?
However, as with everything, critical theory has its limitations. At the root of Marxist theory, for example, is atheism. As Karl Marx famously wrote, “Religion is the sigh of the oppressed creature, the heart of a heartless world, and the soul of soulless conditions. It is the opium of the people. The abolition of religion as the illusory happiness of the people is the demand for their real happiness.” And yet, when we see Marx’s areligious society played out in history, we are left with the deaths of 20 million people under Stalin, excluding those killed by disease, epidemics and war. Similarly, Michel Foucault’s constructivist critical theory speaks of ‘discourses’ that are at work in culture, discourses which determine who we are as “selves” because we allow ourselves to play along in ‘games of truth’. The rules of these games are determined by a powerful elite. He writes about, “various mechanisms of repression to which [we are] subjected to in every society.” Being aware of these discourses which dictate who we are is the first step in carving out your own identity. This is very much in tune with the spirit of our current age. However, Foucault also argues that “All moral action involves a relationship with the reality in which it is carried out, and a relationship with the self.” It appears Foucault is suggesting that morality is subjective. If this is the case, then are we at risk of losing the right or moral weight to call oppressive discourses such as racism, slavery or sexual abuse, wrong across all times, all spaces and for all peoples? In short, Marx and Foucault’s critical theories help to identify injustices we see in the world but fall short in providing solutions to fixing these.
To conclude, I think the gospel is the best answer to the oppression that critical theory helpfully highlights. This is because at its heart is a God who takes injustice seriously, dignifies our cries of suffering and has lovingly condescended to fix the root of the problem at the cross: our sinful human hearts.