“In between the ineffective hand sanitizing he used a common pen sitting on the table to sign in.”
You’re right, staying decontaminated is very difficult. Anyone reading this could understand that simply by taking note of each step that they take when washing their hands after going to the restroom: touching the doorknob of the “throne room;” touching the handles of the hot and/or cold water faucets; touching the soap and putting it back in the dish or on the edge of the sink; shaking off your hands into the sink (where you also brush your teeth); drying off your hands on a towel that you’ve used before (and maybe others, too), and that you’ll likely use again (and maybe others, too). And that’s TRYING to be clean.
No one lives in a sterile bubble, which suggests to me that a LOT more people are going to get infected - including people that wash their hands a lot and take a bunch of vitamins to keep their immune systems functioning as close to design parameters as possible.
It's all about managing risk, and hopefully in a way that reduces risk.