I think you're making the mistake of sample size creep. Most people digging a hole in the sand don't get anywhere near deep enough to be life threatening. Only a tiny fraction ever get that deep, and that is the sample size you need to compare against deaths.

It would be like if we said that 2-3 people die jumping their bikes over a river, but that's just a tiny percentage of bike riders so it's perfectly safe.

There is a specifically dangerous set of circumstances and behaviors that lead to dramatically increased chances of death. That it is rare means that you're unlikely to stumble upon those conditions in your day to day life. If you are digging a deep hole at the beach, you are already part of the tiny fraction of people who are specifically at risk of death.