He was winning until Jim Clyburn (who said he wasn't going to make an endorsement) endorsed Biden a couple of days prior to Super Tuesday.

He wasn't "winning" before that. That's not how the primaries work. The reason it seemed like he was winning is because they run the primaries across a few months instead of all at once.

Bernie had won in states he was always favored to win while the states biden was favored to win hadn't happened yet.

Also the Iowa debacle was conveniently used to deny Berjie the win until it was too late for him to get any momentum from it.

There was no debacle in iowa. There was a baseless conspiracy theory about Pete Buttigeg.

Bernie lost a fair election and you just can't accept it so you're making excuses and bringing up conspiracies. You realize who that sounds like, right?

If the progressive movement is going to succeed, we have to accept where it we wrong. Making excuses won't get us more votes.