It may just be my perception but it seems to me that the verb assumir is or embodies a Brazilian cultural value. People are always talking about the importance of taking responsibility, taking charge, assessing, declaring and facing the reality of a situation.
It seems to me that much academic advice goes in the opposite direction. It is about what not to do, what to avoid, where to dodge, and how to avoid conflict. I think assumir is the better strategy, as it gives you far more power.