I have set up an Editor user and restricted access to the builder to Edit Content. The user can access the builder but is able to delete classes on elements.
I don’t think this should this happen according to the docs as the editor can change the whole page layout if classes can be removed.
I have adapted the title of your report because a user with “Edit content” rights can indeed remove classes, but not delete them. That’s a huge difference. However, the user shouldn’t be able to remove the class either I’ve added it to the bug tracker.
Yes that is probably more correct in removing the classes.
Also another point on this, when an editor enters the builder all the elements are shown on the left but they are all non interactive. Could these be hidden or the whole left side bar hidden perhaps. Causes confusion for the user as is