In general people are critical of ideas that are new. HN has an especially critical user-base with technical skills, so attacks can be made on a larger surface area.
1) Blockchain is not "new". It's 10 years old. We went through the hype cycle for it. The thousands of software engineers and mathematicians on HN have had time to assess.
2) HN is for more accepting and enthusiastic about new ideas than the general population.
2) HN is for more accepting and enthusiastic about new ideas than the general population.