It may not be the Addams Family, but it's close. Most of Tangerine focuses on the dysfunctional family dynamics between Paul, Erik, and his parents. Family has made both Paul and Erik who they are. (Thanks a lot, Mom and Dad.) In Paul's case, this isn't bad, because he's a nice kid. In Erik's case, it's downright dangerous. Like evil dominoes, families shape people, who then shape society. By the end, we know that we'd all be a lot better off with more families like the Cruzes and fewer like the Fishers. Yay! Go love and closeness and all that good stuff!
If Erik had grown up in the Cruz family instead of his own, he would have turned out a decent person, instead of the monster he is today.
Even if Erik had been punished for hurting Paul, he still would have turned out a bully.