And when the religious extremists next come for queer public displays of affection? Are people supposed to only do that in private, too?
It's a book. They can get over it. I won't hurt them if they want to burn LoTR, The Selfish Gene or any other book (or flag) privately or publicly.
Ultimately this is capitulation to threats of violence. It's a rather slippery slope.
If this kind of thing becomes the trend, it will only beget more violence not less. And climate activists using this strategy will be the least of our worries.