I've been out of pocket for a few days, so forgive me for not reading this thread as in-depth as perhaps I should have. That said, part of the confusion may be due to the fact that this is a procedural matter, not (really) a substantive matter
The district court dismissed Tyler’s suit for failure to state a claim. Because Tyler’s complaint validly states a violation of the Second Amendment, we reverse and remand.
That means that the gov't filed a motion to dismiss for "failure to state a claim for which relief can be granted." IOW, a motion to dismiss under Federal Rule of Civil Procedure 12(b)(6). A
very quick and cursory review of 6th Circuit caselaw shows me the following:
6th Circuit said:
Dismissals of complaints for failure to state a claim upon which relief can be granted are subject to de novo review. . . . . All factual allegations are considered to be true. . . . . If an allegation is capable of several inferences, the allegation must be construed in a light most favorable for the plaintiff. . . . .
Mayer v. Mylod, 988 F.2d 635 (6th Cir. 1993)(internal citations omitted)
In other words, on a 12(b)(6) motion, the defendants are basically saying, "Judge, even if you take everything in the Complaint as true, we win. Please throw this case out." For purposes of the motion to dismiss, the defendants do not challenge the factual assertions, but only for purposes of the motion to dismiss. The defendants are free to challenge the factual assertions in the event that the motion to dismiss is denied.
The bottom line of the 6th's decision is: Tyler has alleged sufficient facts that, if true, "state a claim upon which relief can be granted." It doesn't mean he's right; it doesn't mean he automatically wins. It only means that he survives a motion to dismiss.
Now we'll move on to an Answer, the discovery process, probably a motion for summary judgment, etc.