Chicago has strict gun control.
NYC has strict gun control.
DC has stricter gun control than the UK!
The only jurisdiction on your list which has "lax" gun control measures (indeed, no State level firearms legislation) is Vermont; and that's the lowest homicide rate in your list!
Correlation does not equal causation. Look at Venezuela and Brasil; both nations have strict gun control, yet both countries have BIG problems when it comes to homicide. Conversely, compare 3 European countries: The Netherlands, Sweden and Finland. The Netherlands has a very low rate of gun ownership, with Finland having a very high level (and Sweeden sitting right in the middle) but the homicide rate is pretty much the reverse of that!
http://www.bra.se/download/18.656e3...11_15_homicide_finland_netherlands_sweden.pdf
"There seems not to be any clear correlation between firearm
ownership (at least legal firearm ownership) prevalence and homicide
rates in Europe (Granath 2011; Kivivuori & Lehti 2010). According
to the International Crime Victim Surveys, for example, in
Finland, in spite of the high ownership prevalence and relatively
high violent crime rates, the use of guns in robberies, sexual offences,
or assault crimes is almost non-existent (van Dijk & van
Kesteren & Smit 2007, 284)"
Gun control legislation is a feel-good, vote-buying measure, at best.