Trying to understand whether Dorfman's NYer fiction is a story - or an excerpt

Ariel Dorfman fiction in the current New Yorker, The Gospel According to Garcia, seems like a great start to a longer piece and leaves me wanting more - which leads to a question about how we judge short fiction. In a way, it's good that it "leaves me wanting more" - all great fiction should do that, in a way, opening the door to our thinking further about the characters and their world and of course ours as well. Don't we want more when we get to the end of The Dead? Lady with a Lapdog? Big Two-Hearted River? But we also get the sense that these stories gave us just enough, that the rest was on us, so to speak. Whereas other stories leave us wanting more because we simply don't have enough information to make sense of the story - either the author never figured it out himself or herself, or the author just stopped short before completing the piece, or the author tried for one of those vague open-ended conclusions and just didn't get it right. So as to Dorfman's story - an account of a classroom in an unnamed, unlocated school, apparently of kids in some sort of remedial class that all or most must pass in order to graduate that year from high school, in which their beloved teacher, Garcia, no longer presides, and it's the first day for a new teacher, whom the students meet w/ silent contempt, in particular because he has no knowledge of or respect for the Gospel of Garcia, which includes such principles as respecting silence - if it's a total standalone short story I feel I don't know enough about why Garcia is no longer teaching - it's hinted that there may have been some sort of scandal or violation of rules, but perhaps not - nor about who these students are - and how the class will proceed under the tutelage of the new teacher. Yet if this piece is the first section of an anticipated novel - good, these are questions and mysteries well established that will keep me going, at least for a while. Context is never "all," but sometimes context does effect our judgement.