I wouldn't necessarily say that it is "scary." It is just something to think about.
The article is a bit misleading, until the end. There are 2 points to keep in mind:
The new self-reporting error system will certainly create the illusion of more mistakes made. I'm not sure if ATC uses the NASA program or an ASAP program, but either way, when you have the chance to report a mistake and learn about it, and not get punished, you have an impetus to report it. So yes, the incidents may not have increased by 100%, the reporting of such incidents has.
Secondly, this is not just an issue at PCT. The average controller experience level has decreased dramatically in recent years, as the PATCO replacements are all now retiring. I hear training at airports and centers all the time. As a regional jet pilot, it doesn't scare me at all. I was once new. We can't expect everyone to be perfect, we can only try to be.