He didn't read his mind. Doakes was a detective and saw that Dexter was deep in thought. This is a tactic to get the person to accidentally repeat themselves but out loud to hear what they were thinking.
You love saying things have happened without evidence. Back in my day that was called libel and could get you sued, it makes sense why you only pick on the dead.
So, let me get this straight. They blame people of colour for destroying their country... so they destroy their country in protest? Cutting their nose to spite their face much.