Congress actually let the AWB expire,
Point of order here, ..Congress did not LET the AWB expire. They were REQUIRED to allow its expiration, due to the sunset clause written into it. (the one good thing about the entire law)
A lot of people worked very hard to pass new bills to extend the AWB and to make it permanent. THIS time, they were not in the majority. Other people worked hard to ensure the AWB sunset, on schedule, as written. It did.
And after it did, the world did not end.
They can't carve out an exception to free speech,
There are people working to do that as we speak. In fact, some "news" outlet's first question, after reporting on the Texas shooting at the "free speech event", was NOT the familiar "ban assault weapons/ban guns" mantra, but was instead "should we limit free speech?"
Since Heller and MacDonald, the antis have shifted, slightly. These rulings have given a modern reaffirmation to the 2nd Amendment, and they can't do much about that. So the new "holy writ" for their cause is that if you or I have some kind of legal access to some kind of firearm at all, then our rights are not violated.
The same logic would dictate that as long as you were able to worship some God, some where, your freedom of religion was not violate.
OF course, they say "that's not the same thing!" but really bottom line, its about your right to make your own choices, and I see that as the same thing.