Do you even go to church bro? Seriously, though, the 12% saying yes... are likely not in church.
The family dinner bit is terrifying, as is the poll overall. Never has it happened when the four of us are sitting at the table eating. I would probably be smacked with a spoon even today if I was to try, and with just cause. Completely out of the question. During a lecture, it is a given that you will (provided the professor hasn't explicitly or implicitly prohibited it), but in a smaller class, it's not something you want to do. You can go an hour without looking at your phone (but no-one texts me, anyway...) but if you really have to you can run off "to the bathroom" and check it there.
In a business meeting, no, unless it's some long board meeting, I don't know. I'd attribute the millennial score to having not been in many business meetings, either having not worked or working in some hipster wishy-washy open plan office where a formal meeting might imply a one-on-one thing (i.e., getting fired).
As for church... no.
I go to church and check my phone during it all the time. I voted for that and dinner (depends on circumstances there)