I don't think passivity is good. We can take this word in a broader sense to mean a passivity toward life in general, not just with respect to action, which usualy leads to depression.
Aristotle made the distinction between active life and contemplative life. He said both these kind of lifes have their advantages and particularities. On the one hand, a active life is good for the development of virtues and happiness as the goal, because virtues are habits of actions, thus in one sense, it is very true that without action one can not be a virtuous person, and therefore he can not be happy, because virtues leads to happiness.
On the other hand, Aristotle argued in favor of contemplative life as a prim mean, and secondly a life of activity, but in the shaddow of the contemplative life.
But very few people are able to live and enjoy a contemplative life. The only ones that naturaly enjoy contemplation are INTJs and INFJs, because they have Introverted Intuition, which to Aristotle meant "contemplative intelligence", and he defined as the highest form of intelligence.(I know, controversy time, but this is what Aristotle argued).
Aristotle (who was a INTJ), said that contemplation is a activity of reason, found not in action, but in reason itself, and pleasurable in itself, not for something else outside of it. As a INFJ, I can testify this is true: the best moments I had was when in quiet contemplation, when I would just think contemplatively at something, or anything, with a very authentic feeling of satisfaction and joy inside myself. Of course, this doesn't happen all the time, but very rarely, when I don't have any "wordly" worry, and I can peacefuly contemplate.
I am not talking about beng "dreamy" or "dreaminess" here. That is different from contemplation, very very different.
So if we take passivity to mean contemplation, then yes, there can not be anything bad in it. After all, isn't this what a philosopher does, he quietly contemplates and observes anything, enjoying that he discover things which few people know? Knowledge is the treasure of the philosopher.
But still, even a life of contemplation only, without action, is not good, as Aristotle warned. This is because the development of virtues are to be found in the habits of action, and virtues lead to happiness, conform to Aristotle. Because virtues are paths to which morality is expressed, and morality is just action, in one sense.