It is also not true that “Chicago, Detroit, Washington DC, St. Louis, and New Orleans” have “extremely strict gun control laws”. Before the Heller decision, that was true of Washington, D.C. (which is not only a city, but also a state-like entity with home rule since the 1970s); even after Heller, the District of Columbia still has fairly strict gun laws, at least by American standards. (A U.S. Court of Appeals ruling from last year will further weaken the District’s laws–or further move D.C. in the direction most of the rest of the country has already taken, if you prefer–by making Washington a “shall-issue” jurisdiction with respect to concealed carry laws. I don’t know to what extent that decision has been fully implemented; at any rate, the D.C. concealed carry laws still look pretty strict in many ways compared to other “shall-issue” jurisdictions. [PDF file])
Chicago also had strict gun control laws before the McDonald decision, but they have now been substantially liberalized; and Chicago’s ability to control owning or carrying guns within the city is limited. Illinois as a whole does still have fairly strict gun laws in several respects, for a “shall-issue” jurisdiction [PDF file], but Illinois is nonetheless–like most of the rest of the country–now “shall-issue” after another U.S. Circuit Court decision a few years back.
(It is certainly true that the previously strict gun control laws in Washington, D.C. and in Chicago did not actually keep those cities from tending to have murder rates that were frequently high even by U.S. standards.)
Otherwise, most gun laws in the U.S. are at the state level, not the local level. Over 40 states have “preemption” laws that largely ban municipal or local governments from regulating firearms one way or the other (typically, the only exceptions will be for “discharging firearms within the city limits” type laws; and even those kinds of regulations will often be required by state law to have exceptions for legitimate use of firearms in self-defense). So claiming that Detroit, St. Louis, and New Orleans have “extremely strict” gun control laws is not true–those three cities have the same gun control laws as Michigan (moderately strict by American standards, with registration of handguns and universal background checks for handgun purchases, but no “assault weapon” laws or magazine size restrictions, no registration of long guns–rifles or shotguns–and a “shall-issue” law concealed carry which also automatically recognizes the licenses of license-holders from any other state); Missouri (a “constitutional carry” state where no license is required to carry a concealed firearm in public and with generally quite permissive gun laws); and Louisiana (a generally very “gun friendly” Southern state). It may well be that politicians in those cities would like to have stricter gun control laws, but they aren’t actually allowed to do that by the laws of the states their cities are in.
Cities with genuinely strict gun control laws (by American standards) include Newark or Baltimore (because New Jersey and Maryland as a whole have relatively strict gun control laws), and in fact Baltimore has a very high murder rate; on the other hand, New York City (which has had strict gun control laws for decades) has gotten dramatically safer in recent years than it was back in the Seventies or Nineties.