It is still an option, not obligation, meaning that despite Marotta's words if Pereyra doesn't play well till the end of season (so far he's been more than a decent) we can back out.
Anyway, if he'll be our only acqusition for the summer for that role then you're fully whithin your rights to express disconent, as we can do better, should do better, but since we're asuming here I assume it won't be the case and that we're actively seeking for better players for that specific spot.
Until there are better opportunities during the summer Sneijder will do just fine and we wouldn't be paying transfer fee, or few mills tops, which makes him affordable for the time being. At 30 years of age (was surprised to see that he isn't older) he still can offer top quality football.