I didn't see "or completely replace the device" on that page. From the article This suggests a few ways to defeat this tracking method. 1, filtering javascript. 2, finding where the value is stored and preventing the browser from doing so, possibly by file/folder permissions.
Probably you know, but they refer to setting sync by itunes when they said "completely replace the device". And though your suggestion are probably right, 1. can't be applied to whitelisted site (of course you should whitelist only trustworthy sites though), and 2. currently there's no such handy addon except for disabling HSTS. Maybe Proxomitron or its alike (such as Privoxy) can do it but you need to make new filter. I'll wait some dev implement such anti-tracking capability into his addon.
From the article: That's incorrect for Firefox on Windows. How to clear HSTS Settings in Major Browsers From Mozilla Bug 1114786:
In Firefox, it's possible that a site has site-specific information stored, but doesn't appear in the about:permissions site list. If you want to be sure that all site-specific information for all websites is deleted, use History -> Clear Recent History and check 'Site Preferences'.
In my past experience on Chrome, actually when I deleted ANY of history data (either cookie or history or stored password or...), HSTS settings were deleted. It annoyed me because I wanted to save my HSTS settings for cert-pinning.
