The number of people who have even heard of "federation" or "Mastodon" is a vanishingly small fraction of the target audience for this app. Why waste precious page space on it?
To be honest, I fail to see the value of Threads considering both Facebook and Instagram already exist. Is this just "Instagram but the image posts are optional"?
Some kind of "explore not just Instagram but also the rest of the world" take could work to advertise their new network, maybe painting their shitty company in a better light.