While I don't think that the author of the piece meant it this way: If I believe in Karma, arguably I believe that the best thing I can do is to fulfil my stat

While I don't think that the author of the piece meant it this way: If I believe in Karma, arguably I believe that the best thing I can do is to fulfil my station in life as I aspire to break the cycle of rebirth. It's definitely worth remembering that Karma existed in a society that did have, and still does in some ways, a very strong caste system where the good of the society was often seen as a consequence of everyone doing their assigned role. Notably, in the Bhagavad Gita, one of the arguments that Krishna uses to convince Arjuna that he should fight against his own family is because it will fulfil his verdic duties - in this instance his station in life as a warrior.