I saw nobody was using it, so I even tried to make it more obvious by turning it yellow and putting a 👉 next to the checkbox. Would you rather see it underneath the box, just above the post button?

That would probably be better. Especially since people are used to those little boxes above submit buttons for things like terms of service, opt in, etc.

I can see a dilemma though since the checkbox actually changes the text. I get why you'd put it at the top. Just isnt how my brain worked due to prior UI conditioning. I would put that box right above the two buttons and see what happens.