Of course, this is true. When you see pictures of people, like profile pictures, smiling people elicit more empathy than if you look like you used a mug shot on your arrest report.
Yes, John smiles and more often laughs a lot. But what is better, he makes you smile or laugh a lot. People like following his blogs and Facebook groups because you are going to end up smiling or just laughing out loud because of his wit and great humor.
People want to laugh and smile and feel good. John gives that to people.