Blocking roads is a popular and effective protest means. Would you say the same about black lives matter or the current anti trump protests? You are being hyper selective.
The message with the art is that it won't exist if big oil isn't stopped. It's also an easy way to get in the papers without actually damaging the actual artwork.
And now we find ourselves in a situation where common people think protesters are the enemy and countries are powerless and can't help the situation because it's all the fault of global industry. Guess we could just give up and forget about it if those pesky villains weren't constantly throwing paint on bullet proof glass.
What a joke. You are a mouthpiece for the oil industry and part of the problem.