if you look at the image it explains that it’s a safety harness demonstration… the whole joke is taking the piss out of a slackjaw propagandist

The Gordon Chung post is almost certainly fake–if you check the Wayback Machine for the tweet you’ll see it was just a screenshot. Not only did I fail to turn up the original tweet from Chung, someone else mentioned contemporaneously in the replies to the tweet in the OP that they couldn’t find it.