Well, here's where things get interesting. A lot of current Social Justice language originated in Academia, and thus even out in the real world the proponents of these ideologies tend to persist in the usage of this language. Even in situations where it doesn't apply. To them, there is no such thing as just plain old racism, for example. The only racism that exists, or at least that matters, is institutionalized racism. This is where existing political or governmental systems can seem or even actually be stacked against a person or persons of a certain ethnicity or sex. Regardless of how they came to be or the reasoning behind these appearances, such things exist. The black population in the prison system is far higher than white population. It's difficult for trans-individuals to have their gender identity recognized. All valid examples.
The problem happens when a person of this mindset refuses to believe that individual racism exists, or can be anything significant. The same people who will call out a fallacy of relative privation when addressing the standards of living for women in the western world versus those in the middle east will steadfastly refuse to believe that someone who is not a minority can be discriminated against, or cannot be discriminated against to a degree that will significantly impact them. Just because you feel someone's plight isn't relevant doesn't mean it isn't relevant to them. Human beings, in all their diversity, are built from the same chemical building blocks on the same basic template. To suggest that someone is incapable of holding discriminatory beliefs is to strip them of a part of their humanity, even if that's an unpleasant part to imagine of them. Humans deserve to be considered capable of both good and bad acts.
The most amusing part of this mindset that I've seen is where they will unconsciously be racist themselves by lumping together many nationalities and ethnicities, assuming them to be one pure, innocent whole, and ignoring cultural attitudes like Korean anti-Japanese racism (and vice-versa), tribal/ethnic conflicts in various parts of Africa, or how North-East Indians are discriminated against by other parts of India due to having more Asian features. The world is full of diverse and beautiful people who are flawed, complicated, and cannot be generalized with one broad sweep, regardless of how noble you think your intentions may be. **coughtumblrcough**
So while your Sociology 101 course may teach you all about cultural oppression (believe me, I've taken the course), and your academic definitions may work for some situations, they don't work for all situations. The world is a lot more complex than slapping labels on things and tweeting a hashtag. Generally, what we can do as individuals is remember to never be an asshole to someone based on the circumstance of their birth, and never forget that people are capable of being assholes to one another based on the circumstance of their birth. I openly admit to being an asshole, but generally I'm only an asshole to people based upon merit.
I feel this really should end with a musical number. Lighten the mood and all that.