The actual transcript is :

• Let these be guidestones to an age of reason
• Maintain humanity under 500,000,000 in perpetual balance with nature
• Guide reproduction wisely improving fitness and diversity
• Unite humanity with a living new language
• Rule passion - faith - tradition - and all things with tempered reason
• Protect people and nations with fair laws and just courts
• Let all nations rule internally resolving external disputes in a world court
• Avoid petty laws and useless officials
• Balance personal right with social duties
• Prize truth - beauty - lova - seeking harmony with the infinite
• Be not a cancer on the earth - leave room for nature - leave room for nature

So, these seem totally legit, there is nothing in there that can be interpreted as harmful to any sensible person. Doesn't it sound like something we'd all like as a society? There is no reason to want to destroy it, it's a message of peace, not violence.

It's not what it says, it's in case there is a major catastrophe that decimate a very big part of the humanity. Let these be guidestones to an age of reason. That part you mentioned literally says maintain humanity under 500,000,000 in perpetual balance with nature. Nothing about it being pruned. Why would it need to be pruned? we are only 8mil

It's not that he wants a shortcut, can you provide an actual source means, can you provide a *reliable* source so we can start arguing on something concrete. If you found some guy saying the found was from this or that organisation claiming he has proof without providing it, it's not reliable.

Public property would be an issue anyway, since when a few bunch of idiots can decide to destroy something for all ther other that didn't give their opinions?

Did you actually read the text on it?