Rowles was arrested during an investigation by counter-terror police into extreme right wing activity using social media apps.
Rowles wrote offensive messages about Muslims, including a message where he said “bomb mosques”.
In one expletive-filled message which included an extreme racial slur, he wrote, “they should all be strung up or shot”.
The court was told he described himself in an online profile as a 16-year-old skinhead neo-Nazi and a loner.
His profile photo was of a young white man wearing a face covering, there was a German flag and the words “right hand path always”.