This is only ever a problem when the thing they’re being asked to do for ‘exposure’ is normal paid work. In this context nobody is being paid, their work isn’t enriching someone else, they would be contributing like all the lemmy devs, the server operators and everyone else contributing to the operation of the site. Nobody’s approached a specific artist and requested they do this for ‘exposure’, someone’s simply suggested that, oh hey, like everyone else that contributes their time to the site, maybe an artist would like to contribute theirs as well.

Pull your head out of your arse.