It does infringe in the 2nd but not in the way that's been said.

Since marijuana isn't legal federally, the ATF's rulings on it include marijuana as a controlled substance still, since it, ya know, still is.

That's true for literally every state with recreational or medical marijuana.

The good thing is that if there's no ID system required for purchasing marijuana, then no one can know provided you don't use traceable info like a credit card.

Technically, you cannot buy or smoke marijuana, medical or otherwise, and own firearms. Reality isn't that cut and dried and until marijuana gets rescheduled, this is the way the ATF is mandated to treat it.