It's a little more complex than that, but it's all relative voltages. The general idea for human safety is just trying to make electricity go somewhere other than through you.
In avoiding blowing up chips you're trying to dissipate static safely and avoid putting bad voltages across things. That's why there's issues with "power before ground" which is why modern connectors have grounded casings or longer ground pins inside them.
So say a chip wants no more than 5v going through it and you have 1Kv built up on your fingertip. If you touch it directly that could kill something, but if your wrist touches the metal, it can dissipate first.
So like for a thing running on battery "ground" is just the low end of the battery, and everything else is relative to that. It gets more complex when you get into interconnected systems, and then you get ground loops and all this other garbage that you have to worry about.