Perhaps the distinction is conceptually vs. in practice. Bitcoin isn't a scam conceptually, but has become a scam in practice imho. Many (most?) other cryptos are both.
It kinda is. For it to work, it needs: -constantly increasing userbase -huge increase in value -constant incoming investment capital They are exactly the same requirements for a working pyramid scheme. So...
That's 'in practice', referring to what needs to happen for everyone to profit from it. In concept, it's simply a tool that began with various capabilities and goals. However I don't know of any foundational bitcoin concept that suggests it should always be worth more than where it's trading at. Enter scam.
It comes with the territory and with the intended usage. When BTC was at $5 and only 3 MM existed, they could only use it to pay for 15 MM worth of products and services. Obviously to be able to function as real money, 1 BTC had to grow huge. So it is not spelled out in its white paper, but it is a necessary conclusion.