This sounds like something to be outraged about but is actually constructive good news: if more people repeat the experiment, someone could invest some engineering time into building a tool that would prune out CAs from browser trust stores. Every CA removed from your browser is one less attack vector.
Also, I assume the OS and browser vendors do some sort of verification before adding a CA to their list of root certs. Is the message that we shouldn't trust their verification efforts? If so, we should probably use something other than popularity to do our own independent verification.
If your browser trusts 100 different CAs, I can MITM you after compromising any one of those 100. If you only actually use 10 of them, then you can remove the other 90 from your trusted list and make my (the attackers') job 10x harder. More-or-less regardless of which individual CAs take security a bit more seriously than the others, since they're all held to a reasonable minimum standard.
Except the ones that are too big to fail right?
or possibly infinitely easier if the users become accustomed to accept ssl errors due lacking root certs.
[1] http://www.mozilla.org/projects/security/certs/included/#CNN...
Do you really want to rely on China's CNIC to make the decision if you should trust a certificate?