The main difference is that startups add value to society through inventions that ideally improve our quality of life and put food on people’s tables through employment. Cryptocurrency investors do none of that; they just mint a bunch of tokens and roll the dice.
Cryptocurrency investors don't, but neither do startup investors. The question then is whether the startup produces anything of value to the world, so the analogous question is whether the cryptocurrency (not the investors) produces anything of value to the world.
I've personally used cryptocurrencies to bypass expensive international bank transfer fees when moving money between family members in different countries. To me, they had beneficial value for this. I'm not saying that's enough to warrant their existence, but saying they literally have no value whatsoever is clearly not true. So the question is whether they provide enough value, compared to startups. In my opinion, a lot of silicon valley startups in many industries (social media and advertising being big ones) also don't provide anything worthwhile to the world, so at least those are about on par with cryptocurrencies.
To me, investing in those startups is no different than investing in cryptocurrencies in the sense that they are equally negative forces on the world.
