Agree. As i recall all primaries until this one had candidates other than the frontrunner getting votes and winning delegates. Back then, no one claimed it meant those voters were leaving the party if their guy didn’t win. Take Trump/Cruz or McCain/Romney... did that mean the end of the line for the gop?
The Nikki campaign and AP are guilty of the “raising the bar” or “moving the goalposts” fallacy.
https://rationalwiki.org/wiki/Moving_the_goalposts