From a purely non-partisan point of view this is a very reasonable stance.
Examples: Tens of millions of Americans think that the something was sketchy about the JFK assassination and many inquiries and commissions looked into it. Many Americans believed that there was something sketchy about TWA flight 800 and a commission and investigation was created. Many Americans wanted to know what actually happened on 9/11 and a commission and investigation happened.
Now, you can debate what was revealed or not revealed in those investigations and such but the fact of the matter but there were inquiries. The same needs to be done here.
Therefore, we have millions of American voters that believe that the 2020 election was rigged so we should have a full scale investigation. It was done for the election in 2016 for 3 whole years with Russian collusion and the like.
Any product from a Biden/Harris administration is unconstitutional.