So Congress can prohibit free speech by 18-20 year olds?

A Federal Judge says a blanket prohibition of 18-20 year olds buying handguns - not just regulation - doesn't violate their second amendment rights:

A federal judge in Lubbock has blocked a National Rifle Association suit that claimed an age requirement on gun purchases was unconstitutional. The judge ruled that federal restrictions barring people younger than 21 from buying a gun do not violate the Second Amendment.

...

United States District Judge Sam R. Cummings wrote the opinion. He wrote, “The right to bear arms is enjoyed only by those not disqualified from the exercise of the Second Amendment rights."

Congress identified a legitimate state interest—public safety—and passed legislation that is rationally related to addressing that issue—the ban; thus, it acted within its constitutional powers and in accordance with the Equal Protection Clause.

In essence, it is within the purview of Congress, not the courts, to weigh the relative policy considerations and to make decisions as to the age of the customer to whom those
licensed by the federal government may sell handguns and handgun ammunition.

Well, let's try this out:

Determining who has the right to petition Congress is a decision within the purview of Congress, not the courts.  How's that?

Or, determining who may be compelled to testify against themselves is a decision within the purview of Congress, not the courts. Cool?

Didn't think so.  Of course, I didn't go to an elite University, so I'm clearly an idiot.  IANL, but I hope that the NRA appeals this.  We haven't yet seen all the dust settle from Heller and McDonald.  But the ruling that you have a fundamental right to keep and bear arms seems like it will ripple through the case law, even to situations like this.