IMHO - It's not about crime. It is all about control and forced regimentation of the segment of the population that hasn't voluntarily walked away from freedom and moved onto one of the the government plantations. The claim of fighting crime is just a convenient cover.
Notice that the real advocates of gun control ignore the data that shows that gun control in laces like Chicago, New York and Washington doesn't work. Or that the old assault weapon ban did nothing to reduce crime.
They cannot win an argument against facts so they appeal to emotion, feelings and hate.