Well I already did the work I'm willing to do on my end. Further research would obviously have to take in to consideration deviations from general population density, but just looking at the map, there's a lot of voter intimidation being reported in the south that clearly has nothing to do with population density.
Also, there's no correlation with voter intimidation and population density for cities in the midwest.
So I guess it's just my word and my graph against your word and, well, nothing else. So you better get to work!