getting in touch with your anger can be a good thing especially if you've spent a lifetime repressing it. dumping it all over others on arguably the biggest holiday of the year that is about peace and goodwill, not so much. learning how to control your anger and to communicate and express your emotions in a healthier fashion is a good goal now. you may have very good reasons for being angry at your stepdad but there are much better ways to deal with it. i do get it though and if you were taught zilcho communication skills it will likely take time and hard work to learn how to communicate effectively. it will be worth it though.

a good way to think about if you should have acted in a certain manner or not is to turn it around: how would you have felt if your stepfather, or someone else, unloaded just like this at you on xmas? what sort of action or acknowledgment would you want from them now that they did that to you? maybe begin to think about writing a letter of apology to both your parents for how you communicated even if you feel what you said was needed.