Basically, we are all bioelectrical organisms with our own magnetic fields (I highly recommend Robert O Becker's The Body Electric if you're curious about the science behind this, I am almost finished and will post a lil book report on it here soon).
If we accept that we have our own electromagnetic fields around each organ as well as around our body as a whole per Becker and others' exhaustive research, then it becomes easier to understand why a geomagnetic storms may affect us. It essentially creates electromagnetic eddies in the fields around us as the storm interacts with our bodies.
These eddies will most affect the places where we have the weakest fields in ourselves. So if you have something like arthritis, then you feel it in your bones like I do.
And let's be honest... Do you think there are many people out here with weak minds for whatever reason? These types of storms will make them feel even more weak and unsteady within their sense of themselves. It'll be similar to the full moon effect where there are more crazies out there. I would hypothesize that these types of storms would have more crime, more drama, and more general fussiness from the population than on any given day without a solar storm.
I hope that was easy enough on you! It's my current special interest so if you have any questions I'm happy to keep going ☺️