I don’t think people should call themselves “rabbi” if they have no rabbinic related role or if they’re not a person sitting and learning all the time. The title has become so diluted that in yeshivos, it’s a mockery. The Harrys who are in college want another certificate to hang in their study next to their degrees, so goes the narrative.
It’s just a few simanim of shulchan aruch and nosei keilim. It’s really not that big of a deal , but the hamon am laps up the title.