Vote count difference between Sanders and Biden, in Texas, was 71K. Rough analysis but closing 750 polling stations in hispanic/Black precints would be apx. 100 voters less per precints voting.
Sanders supporters are working class. The tradional strategy for conservatives is to make it hard for working class to vote by limiting access to the ballot.
I don't believe the Latinos failed to deliver in Texas. Democrats knee capped him there.
Still trying to figure out how a candidate can pull thousands out on a workday can lose to someone who had no organization to speak of and no polling just days before super Tuesday. This would have to be one of the largest political upsets in recent memory done by a candidate who had no presence, organization, outspent and clearly sundowning from the grind of the campaign.
Massachusetts is another amazing swing. Sanders brought out 12k at a rally there, during a work day, and was poised to take over Warren right before Tuesday. Mass does not take it's voting cues from South Carolina. No one saw Biden beating either Warren or Sanders but here you are. Biden ate sh!t in New Hampshire but apparently South Carolina endorsements from the party establishment put him over the top in a state he trailed badly with no organization, ground game to speak off prior to the vote.