This is a wonderful case in point for trying to understand the EFF's examples on internet defamation:

  https://www.eff.org/issues/bloggers/legal/liability/defamation

It walks the line pretty closely.

If nothing else, it basically just reads like a twitter troll who follows activists around. Not illegal.

Interestingly, also, the website basically talks about this guy constantly threatening and filing lawsuits which he never goes through with, so I would ignore this, but IANAL.