Sanders may have withdrawn. That being said Biden cannot officially clinch the Democaric Primaries. He is rougly 750 Delegates short and there aren't enough Delegates in April & May to reach 1,991.
That's not even close to correct. Biden has more than 50% of the pledged delegates among the states that have already allocated their delegates; assuming he gets more than 50% of the pledged delegates in the remaining states (which is all but assured at this point), he'll have a majority on the first ballot.
It is true that enough states have pushed off their primaries into June or beyond that he won't pass 50% of all pledged delegates until at least June 2, but that's trivia at this point.
This is all true. A few points to poster 2016:
A. The original deadline was June 9th. There are now 4 states after that (LA, KY, NY, and NJ). Even if those delegations were all cut in half (not gonna happen), it'd just lower the overall majority number in the process. Even if you don't care about that, Biden will cross 1,991 regardless on June 2nd, so those states voting later have no effect.
B. Even if states
completely cancel their primaries, like NY, CT, and PR are threatening to do, all
that does is further reduce the total number of delegates, making a majority way easier to get to. If NY, CT, and PR all effectively boycott the convention, that just dramatically lowers the magic number and makes Biden even closer to it.
C. Regardless, the delegate penalties to LA, KY, NY (if its primary happens), and NJ are not going to happen because it'd be really, really stupid to do that.
D. So Biden clinches June 2nd rather than April 28th like he would have without coronavirus and the cancellations. So what? He's still going to clinch.