I think the reason is simple: it is ignorance and total misunderstanding of the basic principles of the blockchain. When mankind in the bulk has dealt with this, more has already been done. Everyone who criticizes does it for their own reasons, most simply do not understand what they are talking about. In general, there is a well-known principle "Do you criticize? - Offer!" If, after criticism, there is no alternative that would be more attractive, then such people are simply ridiculous.