Democratic Primaries

And actual scholarly research into the election shows did no more damage to Hillary than any other similarly contested primary. Which is further proven by the fact that she was at one of her all time polling highs coming out of the convention.

https://fivethirtyeight.com/features/election-update-clintons-post-convention-bump-is-holding-steady/
http://centerforpolitics.org/crystalball/articles/did-bernie-sanders-cost-hillary-clinton-the-presidency/

Speaking of which, yeah he met with those who were protesting during the convention: To tell them they need to accept reality and to support Hillary.

https://abcnews.go.com/Politics/bernie-sanders-booed-supporters-ahead-democratic-national-convention/story?id=40857311

Yeah he campaigned for her in mainly in October, probably the single most important point in the general election as that was the lead up to Voting day! He made dozens of stops and even was booed by his own supporters who didn't like Clinton.

https://abcnews.go.com/Politics/bernie-sanders-hillary-clinton-eye-post-election-goals/story?id=43300037
https://www.usatoday.com/story/news/politics/onpolitics/2016/09/30/bernie-sanders-step-up-campaign-schedule-hillary-clinton/91342564/

And if it was too little too late then why was he able to get more of his supporters to vote for Clinton than Clinton got of her supporters to vote for Obama in 2008? To some here on DU, Sanders could have run a non-stop campaign event for her 24/7 from the day of the convention and it still wouldn't be enough.

https://www.washingtonpost.com/news/monkey-cage/wp/2017/08/24/did-enough-bernie-sanders-supporters-vote-for-trump-to-cost-clinton-the-election/