These people think the Bitcoin market is pure speculation with no real usage. They think it's like tulip mania or the beanie baby craze.
That's how a lot of people think about gold, and gold has been around for thousands of years. It's something that doesn't have much of a real utility other than jewelry and industrial use, doesn't produce anything, and is a game of speculators.
It still has a $7 trillion market cap. People are easy to trash assets or things in general they don't need or understand. Bitcoin is exactly like that. Eventually they will take back their words and buy into it one way or another.
People need to be proven wrong time on time again, each cycle. At the end of the day, the use of Bitcoin could admittedly show more signs of strength, but we can't discard how important speculative bull cycles are for this market.
That what people see as something that made Bitcoin fail as currency, makes sure crypto as a whole remains relevant.