Well here I am going to go with what I *think* is the thinking at Mouse Corp.
They don't want kids who are going to buy expensive Princess dolls to come across the XXX Agents. More importantly, they do not want the PARENTS of those kids--you know, the ones with the credit cards, the ones who take the expensive vacations to MouseLand, the ones who buy all the movies--to see those XXX agents.
The XXX Agents are, rightly or wrongly, overwhelmingly portrayed as being primarily the interest of a certain type of otaku that you wouldn't want within a hundred nautical miles of a kid. And MouseCorp DEFINITELY does not want their products associated with that type of otaku. The designer and owner of DollyCorp was perfectly willing to take that kind of otaku's money when money at DollyCorp was tight. It all spends perfectly well, and that kind of otaku is *mostly* harmless. But now MouseCorp is supplying the funding...and what his personal feelings are on that subject, only he knows.