I think they were referring to the fact that those states specifically have what's called Constitutional carry.

https://en.m.wikipedia.org/wiki/Constitutional_carry

Edit: with that in mind, it stands to reason that there are more factors at play that contribute to violence than the presence, or lack thereof, of gun laws. On the reverse side of things, California has a laundry list of gun laws that include places like gun free zones, yet they were the site of several high profile shootings recently. And before someone mentions crossing over state lines to get guns, that is already a federal crime if you don't get an FFL involved.