If you're holding bitcoin because you are an active and supporting part of the community then you can not be called greedy. Buying and selling short term is a different game.
Holding Bitcoin is simply like doing any other business. It is just that you are doing this business on the internet. Besides, I think buying and selling short terms is not greedy either. We talk about profit maximization right? At times you sell your coins when the price is high. So many people do that. It is rather a wise and game of mind. However holding Bitcoin for long definitely affects the value of the coin in the market that is the value rises.