Student or Learner
Below is an excerpt from an article from the economist:
"There are still plenty of diehard anti-Castro figures in Washington. But calling the arguments they marshal threadbare is unkind to threads."
I have problem understanding the last part (unkind to threads). Could anyone explain it to me please? Thanks
This is making fun of the anti-Castro figures.
It means: Comparing their anti-Castro arguments to threads (by calling them threadbare), is even being unkind to threads. It means that their arguments are weak and even thinner than threads.