That is his personal attitude towards the crypto. Anyone can express any idea about anything. May be Bill gate doesn't like the crypto. There are good and bad in crypto. We need a system to filter the bad and extract good from it. I think it will happen in future.
For me, Cryptocurrency to me is a good technological development, depending on how you use it. My advise most times to those who are into crypto, most especially the newbies, is for them not to be gullible. Do not because of the fast and big profit you intend accruing, now decide to put all that you have into crypto.