A scam is a conscious attempt to deprive people of something valuable (usually, money). When Satoshi created Bitcoin, I don't think that what this person had in mind was robbing people. And I think most people would agree about it. Bitcoin was not even a commercial project or something, not was it an investment opportunity. It was a kind of money people would be able to use without involving intermediaries or supporting certain countries by using their money. If people buy Bitcoin and then sell it when the price goes down and then call it a scam, I think it's their own misunderstanding of what Bitcoin is for and how it works, they should not blame Bitcoin for that.