They're providing the residence requirement of four out of six, and that's a decision. Isn't that enough—four out of six, 183 days per year in four years, and tax returns? I don't think you need to look at the intent.
What if the person applies for citizenship and they get accepted into a Ph.D. program around the same time? Does that mean that when they swear their application they're lying if they say that they intend to reside in Canada because they might want to, in the future, go and pursue that education?
It just seems very inappropriate in this global economy. Why would we want to limit someone to not doing that?