If you showed a picture of a standard tower crane to someone with a decent understanding of physics but had never seen one before, they would similarly recoil and go "WTF why are you suspending a bunch of concrete blocks high in the sky on what looks like a pencil thin beam!" and it would take some explaining, OR it would take seeing it regularly for that person to become okay with it.

People don't see this every day, so they don't take it for granted, and therefore it looks insane. Just like tower cranes look insane.

I'm familiar with both of those words. Ok also familiar with the idea of a lever-arm, and this one is too long for my sense of safety.

WDYM?

what does dredging have to do with this?

Barges also typically don't carry tall tipping over things with people on top, and are less flexible than this plastic thing.