I'd be a friend to your friend and spend less time resenting her. Her situation is hers. Yours is yours. It doesn't sound like her situation really affects/affected yours.

Most workplaces have their negative points. Kiss ups who do less than others often get promoted, while the ones who kick *** don't, often. People you think should be booted because of behavior, or lack of productivity, are often kept way beyond their time. People often don't get the appreciation they deserve. Way too often, bosses take credit for work that their subordinates do. People with high level educations are sometimes asked to file or get coffee for a meeting. It can really suck! Yes, we should stand up for ourselves when we feel wronged or abused. Sadly, sometimes those abused are not heard. We can live a life resentful, or we can move on or say "No!" to things. We sometimes must swallow our prides or when we really can't accept something, we stand up for ourselves and accept the consequences. We can say "That is so unfair that I was fired (or demoted or passed over) because I said I wouldn't do X!" We can also say "Well, I may have been fired or demoted or passed over, but I feel really good that I refused to do X and was able to give the sucker the middle finger on my way out". That can often be one of the few satisfactions from a particular situation.