IMHO, this decision was made specifically to create disagreement in the 'pro-gun' ranks, and to cast doubt on the Bruen decision.
It's time to decide if you believe in the basic tenet of the BOR and Constitution that there are inalienable rights for all people, or if you believe 'rights' should all be bestowed by governments.
While no rational person wants criminals running around with guns, and we can make the argument that anyone entering the US illegally IS a criminal, each and every one of us needs to decide for ourselves if we believe every person has the right to self defense, and thereby the right to keep and bear arms.
The argument from our side should not be for narrowing or "reasonable" restrictions on our rights, or even whether an 'illegal' individual violated those restrictions. The argument should be about why they were here in the first place, and whether a crime was committed with the gun. If no crime was committed with the gun, why do we care about who has it? It's just a tool. If it's used in a crime, there are plenty of laws on the books to deal with that.
Some here believe that J6 defendants are being wrongfully prosecuted because they were invited into the Capitol building. Does that same principal not apply to an 'illegal' invited in, with their transport facilitated by the current Federal regime? Obviously, if they commit a crime after entering, that's a different issue.
This decision is INTENDED to divide us and cause dissent. Don't take the bait! Praise it as a decision that endorses liberty, and pursue the immigration issue on its own merits.