I've seen exactly this with some friends and their kids. If they're at a more adult place to eat the kids are allowed to watch cartoons so they don't get bored and start wanting to leave before the meal's even started. The rest of the time they're limited in their screen time, read books with their parents and go out to all sorts of fun places like nature parks etc.
It's lazy to judge parents just because you see a 30 minute slice of their day