It doesn't say exactly that. When you apply some logic rules to the given statements, it does say that if he is not morally virtuous, he will take some other action to get into heaven, slay a demon or something.
Looking in more detail at the statements...
1) If you are morally virtuous, you get to heaven, great. This does not mean that you can't get to heaven in another manner. If DOG then ANIMAL, doesn't mean that you can't have an animal unless it is a dog.
2) If you are not virtuous, your longings are satisfied. Same as above, this does not mean that your longings can't be satisfied another way, but the third statement says that your longings won't be satisfied if you don't go to heaven, so if you are not virtuous, he must find another way into heaven or the statement given (not virtuous -> longings satisfied) will become invalid. Since that statement is given as valid, he's going to heaven.