CiviCRM profile "used for" options are not allowing a CiviContribute option on wordpress
Yeah it seems a little weird. It seems to get those options to show you need to first create a contribution page and check the options related to those. So:

For soft_credit, you need to have an existing contribution page with the Honoree Section Enabled checked.

For on_behalf, you need to have an existing contribution page with the Allow individuals to contribute and / or signup for membership on behalf of an organization checked.

For civicontribute to show, you need to have an existing contribution page where the profiles tab has already been set to use a profile.

But in any case they seem to be just visual indicators that indicate that you have a page that uses it.