Whilst I admire his boldness, that’s an extreme stance. Being easy to contact is a good thing, but that doesn’t have to require the publication of your phone number. There’s a middle ground. I can be reliably contacted via email or Twitter — I read every mention in my timeline and read every email that arrives in my inbox.
If a conversation needs to be taken further, I can give out my phone number privately to the other person. If someone wants to talk to you, they will talk to you. There is no need to publish your phone number publicly online.