The OP actually asked two questions: why doesn’t disable/enable “take” for certain extensions?, and why don’t toolbars stay closed if I closed them in the last session?.
You addressed the first. But is it really possible for an extension with load_on_start set true in its registrar code to override the Extension Manager’s enable/disable setting? That would be distressing, especially since the Ruby API documentation stresses that you should have a very good reason for ever setting this argument to false. I thought that the EM’s disable would prevent loading the rest of the code even though the registrar is loaded.
Regarding the second (which the OP confuses a bit by referring to View/Toolbars, which is View/Tool Palettes on Mac), of course an extension can’t show its palette if it doesn’t load. But if it does load, the extension can control whether its palette shows without regard to the state when SketchUp last quit - as you showed. And yes, if the extension is encrypted an end user can’t do anything about this behavior.