I agree with you. These ulemas do not know about cryptocurrency so they call it haram. If it is haram, then gold will be haram.
The stock market will be haram as well. I think the stock market and cryptocurrency work almost the same way.
When the purchase order in a currency is high, the price goes up. Similarly, when a lot of people start buying shares of a company, its share price goes up.
What do the ulama say about this?
There is a saying "Drink deep or taste not the pierian spring".. Our Ulemas(most of them) do have this tendency to pretend having alot of knowledge but actually they don't and less knowledge is more dangerous.
Actually, the problem with our Ulemas is that they have little knowledge and that is more dangerous than having no knowledge. In my opinion, future might b haram but spot is just like buying any other physcial coin which is very legal.