The Supreme Court only answers the questions posed to them, not the merits of the underlying case, so the article's surprise that they're not addressing anything else is a strange to hear from a lawyer. It's also surprising to hear this as a "blow" to the Sixth Amendment, as the justices seem to believe they've rejected exactly this logic before in Monsanto. [1] One good thing is that the article hlepfully linked to a transcript of the hearing, a good journalistic practice too often ignored. [2] In the quotes below I've elided sections for clarity, as marked, primarily to remove where they repeated words or such while speaking.

The case involves Sixth Amendment [3] claims regarding asset forfeiture where Petitioner allegedly defrauded Medicare. The Deputy Solicitor General supports freezing this money so that it doesn't become unavailable to pay back the amount allegedly defrauded. Petitioner wants to use it to fund their legal defense. They retained the services of Howard Srebnick, Esq. for this oral argument. [4]

The argument in favor of the seizure is roughly this:

JUSTICE ALITO: [Two twin] brothers rob a bank. They get $10,000. They split it up, $5,000 each. And on that very same day, it happens to be their birthday, and their rich uncle comes and gives each of them $5,000 as a birthday present. So they go out to party, and one of them ­­ and they both spend $5,000 partying. One of them spends the money from the bank robbery. The other one spends the money that was given to them by their rich uncle. And your position is that the one who spent the money from the so­called "tainted assets," the money from the bank robbery, is entitled to use the remaining $5,000 to hire an attorney, but the other one is out of luck?
MR. SREBNICK: Yes [...]
JUSTICE KENNEDY: So [...] you want this Court to say spend the bank robbery money first.

The argument against is roughly this:

MR. SREBNICK: Justice Ginsburg, from a constitutional perspective, I don't think that that's necessarily correct because the courts can give injunctive power to restrain assets, even assets currently belonging to the defendant. Our objection is when such an injunction interferes with the constitutionally protected right to retain counsel of choice. And so while the statute could constitutionally allow, provided that there is adequate hearings, et cetera, the restraint of even a defendant's owned assets, lawfully owned assets, that principle can't extend to assets ­­ the subset of assets she needs to use counsel of choice.

[1] JUSTICE KAGAN: Mr. Srebnick, this goes back, I think, to the Chief Justice's first question. It seems that the distinction that you're making is one that the Court explicitly rejected in Monsanto.

[2] http://www.supremecourt.gov/oral_arguments/argument_transcri...

[3] "In all criminal prosecutions, the accused shall enjoy the right to a speedy and public trial, by an impartial jury of the State and district wherein the crime shall have been committed, which district shall have been previously ascertained by law, and to be informed of the nature and cause of the accusation; to be confronted with the witnesses against him; to have compulsory process for obtaining witnesses in his favor, and to have the Assistance of Counsel for his defence."

[4] http://www.royblack.com/attorneys/Howard/Srebnick/