why do they call it cohost when you co post in the post co host host the post?

writer / musician / thinker-about-stuff / weirdo on main
I'm!! around!!! and always like to brainstorm, world build, character create, and generally just love having new creative partners to bounce ideas off of (nsfw incl). Please please if you do wanna chat hmu with an ask or smth, i love to make new friends!
i have an AD here I should use...but honestly tempted to just be a freak on main here .... talk to me about TF and hypnosis and corruption and uhhhhhh lots more haha,
why do they call it cohost when you co post in the post co host host the post?
many chosters are co posting this
why won't hosts address these chosts?

how much post could a post host chost if a post host could chost posts?