1. People are afraid of their current skills and knowledge becoming obsolete. This is similar to people being hostile to the cloud 10 years ago and serverless 5 years ago.
2. People are bitter because they see others profiting from the current crypto boom/bubble, and they didn't buy into it early enough or at all.
3. People are genuinely worried about the darker aspects (non-renewable energy usage, scams, illegal activities) and for some reason they blame the technology rather than the actors actually engaging in those activities.
4. People are problem/solution-oriented rather than vision-oriented. If they don't see an immedate relationship between an existing problem and a technical solution to it, they don't consider the new technology to have merit.
These are just some theoretical reasons I think might explain people feeling so hostile.