Also, I'm guessing you haven't actually read the article and are assuming that this is about the Kobayashi incident? If so, fair enough, because I assumed the same thing too. If this were a protest regarding the Kobayashi yellow flags incident then you'd be right in that it's dodgy to wait until after the race to appeal (although I still don't think it's "wrong"), because everyone knew about that situation during the race.
But this is about a separate incident of Vettel overtaking under yellows in the same race. In this situation he's overtaken Verne under yellow flags, so Ferrari are only on the verge of appealing now because it probably took a while for it to be brought to their attention and they want to make damn sure they have all the evidence before they make a protest.
Besides, the official rules of F1 specifically stipulate that protests that might affect the standings of a world championship must be made before 30 November, so they clearly accept that fact that things might be missed during and immediately after the race.