> If it is fiction, why is it so popular among technical people like people who come to HN? Are the people on HN who are interested in Buddhism aware it is fiction/real?

Because it sounds cool and intellectual.

This is the same reason crypto-buddhist "philosophies" became popular in the Hindu-sphere post the decline of Ancient Vedic religion, which had no concept of rebirth and rather focused on Rta (cosmic / natural order), vrata (duty), kratu (will) etc...

Looking enlightened is more important than actually being enlightened.