The analogy isn’t equal. Guns are a right that is spelled out, drug use is not.
Once you can ignore the constraints of the Commerce Clause and the 10th Amendment to engage in a federal drug war, you can ignore the 2nd as well to grab guns. And both are rationalized in the name of public safety. That's the problem - you wish to unleash the federal beast when it suits you. But the beast can then be used for someone else's bidding when they get control of it.