No, not failure at all :)! Just learning…it’s a lot of new information and things like licensing are not always readily apparent. And, like anything these days, there are less than scrupulous people out there — not that all non-GPL themes are necessarily that, but as the article points out there are bad actors. Just stick to the free or recommended commercial theme vendors listed on this site and you’ll be fine. Sorry if you spent money already.
Unfortunately, plug-ins can also be problematic — definitely only use ones from this site and even then, look at the number of downloads and reviews (though those don’t always mean much, but it’s a start). You can also look at forum threads for a certain plug-in — from the plug-ins page on the lower right side, the button “view Support forum” finds threads about that plug-in. If you have particular concerns, just ask on the forums.