When lawyers make demands they often don't have the law backing them. When there's no consequence for making spurious and vague legal threats, the system is going to be abused.
Edit: It's unfortunate, but ... yeah. It might be worth forwarding your story to some legal blogs that specialise in free speech I suppose, but other than that. shrug I'm afraid I'm not sure what you can do if you don't have the money to fight them.
If there were non-criminal consequences for making spurious and vague threats, lawyers would just make legal threats involving those consequences as a response to threats made to lawyers.
Edit: It's unfortunate, but ... yeah. It might be worth forwarding your story to some legal blogs that specialise in free speech I suppose, but other than that. shrug I'm afraid I'm not sure what you can do if you don't have the money to fight them.