re:
Bernie's supporters demanded that she suspend her campaign. However, now that the shoe is on the other foot, Bernie insists on continuing his campaign
AFAIK, Bernie never demanded or even
suggested that Warren suspend her campaign. If we're going to attribute to a candidate what some of their supporters say, well, there were a bunch of Biden supporters here suggesting Sanders drop out even before Iowa! Equating what some supporters once said to what a candidate is saying is just silly.
re:
Just two weeks ago, he said that a mere plurality was sufficient to win the nomination. Now? Not so much.
No, he has continued to say the same thing, even after Biden pulled ahead. See:
https://www.cbsnews.com/news/bernie-sanders-says-joe-biden-should-be-winner-of-democratic-nomination-if-he-has-plurality-of-delegates/
Biden is going to be the nominee. These continuous (and often misinformed/misinforming) anti-Sanders posts are merely divisive, IMO.