Because they risk being bullied or left out. Denying their kid a phone only works if all the parents do it.
Edit: I don’t have a solution; maybe an anti-bullshit law that punishes people from spouting bullshit? (Good luck religious folks!)
But denying a phone may just replace one problem with another.
I personally fucking hate it. But my whole friends group use it for events (bad, birthdays), and messenger chat.
How do you convince ~30 people to switch to something else?
What app do they switch to?