I read about this on the SCOTUS blog and it really stood out for the reasons you mention. But there was also the part where one of the justices mentioned that they'd always construed the parts of this statute narrowly and the FCC counsel actually said that they're prefer not to interpret personal privacy too narrowly due to their broader interests (i.e. not wanting to gut it for everyone), only to find out later that the justice was essentially trying to help him argue against AT&T's arguments.

Like you said, highly unusual.