understand that there is nothing about the act of destroying ancient artifacts that is inherently left or right wing. these "just stop oil" so called "activists" are really just retarded sadists and vandals who live to make the lives of others miserable and to destroy things of value. there is nothing inherently left or right wing about what they do. they are just pure stupidity and evil.
they call themselves leftist because they feel this is what is going to give them the best moral cover for their evil because the left is in power - but they aren't actually leftist - they are just sadist.
to acknowledge their claim of leftism while executing them would be to give left the martyrs they need. instead pretend you do not know what their politics are and you simply executed them because you love the Stonehenge or something.
in fact, for bonus points before executing them attend some left-wing rally promoting the same exact policies that the people you execute have promoted. make sure to be caught on camera doing so. this will confuse the retards real good.