Might need to blow them up, they weigh tons and would require large equipment to take them down. Maybe some excavators dig a ditch around them and then push them it the ditch….just some ideas.
maybe a lawful protest where hundreds of anons piss on the guidestones.
Remember to wear a mask…maybe a headscarf too, keep all skin covered to disquise your race…and dont forget your gloves and steel toed boots.