I replaced them with pastel colored variations of my Fresh theme (which was partly based on a theme emma made). I figured that was the best way to go about it, so as to not affect normal usage of the site.
So now all the forums that were set to use SW's 9 themes are using the pastel themes instead. Change your forum's themes if that's a problem. Derivatives of the removed themes designed by other users are not affected.
Thanks to the 2 users that helped with this.
From now on, all themes contributed by users to the community will be considered public domain. A notice was added to the wiki.
If anyone wants to have a go at making a new material theme for raddle, here are the guidelines: