Bullshit.

I'm a parent. The first time my kid catches flak for not having a smart phone he's going to say exactly what we practiced, "my parents are crazy, they won't let me have one. It's so stupid, I hate them".

The other kids will find something else to pick on even if every kid has a phone. Period. Children are monsters. It's not worth letting your kid's brain rot and have them try to off themselves when they're a teenager because they never had a chance at being well adjusted just to avoid them getting bullied about phones in particular.