I personally don't think it's useful for centrists to teach Bernie supporters a lesson on why he lost, I mean the vast majority who voted for Bernie get it and will vote for Biden. Also most of the points in that post sound like they came from 2016 and ignore the fact that Bernie wholeheartedly endorsed Biden and it was gladly accepted.
It might be more useful to think about what Biden can learn from Bernie. How can he appeal to Bernie's massive donor base? How can he attract Latinos and younger voters? Can he build a similar grounds organization? (You can debate how effective it was too). If we believe in M4A is a North Star, how does Joe present a plan to get there?
Things like that