As for him preferring to play PF, firstly, he never said that. What he said in the interview is that he wants to improve his skills so he can play PF, TOO. Secondly, who cares if he does want to play PF. The players don't pick the position they play. The coach does and it's my guess that most coaches would put him at center. And really, what is the difference between the two positions? Davis is more of a shotblocker, anyway, so the Raptors need a more positional defender at center, and that's Kanter.
As for your logic about few European centers not becoming All-Stars, I can't tell you how flawed it is. The first flaw is that the number of European centers that have come into the league is much, much smaller than American centers, so obviously you're going to have fewer All-Stars. In fact, I'd hazard a guess that the percentage of European All-Stars is around the same percentage, or possibly more, as American centers.
Besides, according to your logic, Houston shouldn't have selected Hakeem #1 because there had never been an All Star African center. And San Antonio shouldn't have selected Tim Duncan because no player from the VIrgin Islands had ever been successful. Dallas should have kept RObert Trayor instead of trading him for that German guy because no Garman had ever been a successful NBA player. Really, what were those teams thinking!