Basically, the long description is:
A attacks B for being X or acting in X manners. But, while A might not be aware of this, from the outsiders' point of view, A also is X or acts in X manners as well.
So, how would you, in a few words, generalize/describe people like 'A'?
The first English word that came to my mind was 'hypocrite' but after checking with Oxford Advanced Learner's Dictionary, I'm not so sure if it is the right one for the described situation anymore...
Yes, normally you would call such a person a hypocrite (exceptions include situations where actually the same standards should not apply for both persons).
However, hypocrite is a wider concept, that can be applied to anyone who is doing something different to what he is saying (in the domain of moral and ethics). So, to be a hypocrite I don't even need some specific person B, all I need to do is to claim that I have certain moral values but to disprove that through my actions.
It is completely appropriate to use it for essential moral values, but also for trivial things as well, for example if I point you to read the faq on this site, but have not done that myself, it would be justified to call me a hypocrite.
There are many other phrases: 'to have double standards', 'to be two-faced' or simply phoney; see other synonyms and near synonyms of hypocrite here.
"The pot calling the kettle black" Also from the bible : Matthew 7:3 "And why behold you the mote that is in your brother's eye, but consider not the beam that is in your own eye?"
You can also call the person a "Pharisee", after this biblical proverb. I find that a lot of people do get that reference.
Interesting answers, but none of them seem to answer your question. You are describing the psychological effect called "projection."
"Projection" means attributing one's own negative actions, feelings, etc. to another person. This is usually a defensive action. Let's say I am rude to waitresses. However, I think rudeness is a bad thing, so I don't want to admit to myself that I am rude. Subconsciously, I want to defend my ego from a negative self-image. To do this, I make myself believe that other people are being rude and that my behavior is acceptable.
Another way to describe "projection," using your example is as follows.
"A attacks B for being X or acting in X manners. But, while A might not be aware of this, from the outsiders' point of view, A also is X or acts in X manners as well." In this case, person A is projecting his or her negative behaviors on person B.
Not a single word, but intolerance of the oppressed might be the concept OP is looking for.
I think such behaviour is far more common than most people would like to think, which might be why we don't have a variety of standard single-word terms.
Poor people in pre-war Germany, for example were easily seduced by Hitler's rabble-rousing against Jews. And American "white trash" tended to sympathise with the KKK rather than with their black "brothers in poverty". But we don't normally call this "hypocrisy".
