The “number of registered voters compared to number of actual votes counted” theory is based on graphics and screenshots that have pre-election day registered voter numbers. Most States had same day registration. Its a shaky theory right now because nobody that I am aware of has compared counted vote numbers to post-election day registered voter numbers (or have even determined the public availability of these numbers at this time).
Right now, the theory being pushed on social media by leftists because leftists know its a shaky theory(and probably has been made unprovable) and are now using it to make the Right look like fools.
“is being”