Hi Davina,
Thanks for sharing your process. I think you shouldn't feel as if you can't comment or disagree, but you should be conscious of your word choice and emotion. If we post or comment in the heat of the moment, we may say stuff we regret later. If we write it, like you said, in your head, or even as a draft, then you will be harnessing your anger. I agree that when we are angry or moved by something, we sometimes have a great comeback. That's why it's good to capture it and then think about it calmly. BTW, not that I always follow this advice. But I am trying to be more conscious of it.
Deborah