There are tests for getting a Super Licence (aside from those needed to get the Category A licence below it) - you're supposed to have 300km of F1 car testing at representative speeds before application. Note that it doesn't have to be organised by anyone official, nor does it need to be a particularly modern specimen (though any machine before 1986 doesn't count because those are considered to be historic cars). The problem is that there's a clause that allows "exceptional" candidates to then obtain the Super Licence without any race skill other than that needed for a Category A licence, if the Formula One Commission agrees. Naturally, a lot of people assume they classify as "exceptional" even if they do not. So I can see why the argument of dissuading incompetent candidates would work, since it would reduce the amount of pointless work that the Formula 1 Commission has to do.
Still doesn't explain why increasing the cost-per-World-Championship-point is meant to help dissuade people who aren't yet in the World Championship.
Incidentally, Yuji Ide won the Formula Nippon series before joining F1. This is one of a myriad of high-level performance combinations spanning GP2, Renault World Series, IRL, Champ Cars and F3) that allows a driver to apply for a Super Licence without let or hindrance from the Formula 1 Commision, provided that they do the 300km in an F1 car and fulfil a handful of fairly tedious requirements (such as paying their fees and getting a medical at the start of the year).