Many people choose these names based on what they want.
If someone is writing about love, they would use names like loveislove to attract readers. Secondly when you see a name like onegoodwoman, liveyourlife, healthguy, asksuzzy, awful poet, uninvited writer, easydoesit, it gives you an idea about what you're likely to find on their page.
Secondly people use simple names that they can remember and names that people can associate with. Names like froggy, hope22, can be remembered.