

It’s a combination of two things, the subversion of expectation, which is a common device in jokes, and the criticism of authority, which is another, similarly common, one.
In my comment, I’m pointing out that these cameras are a risk for even broader abuses than just subpoenas, and compliance with law enforcement requests under the guise of finding lost family members.
The responder humorously twists my words to claim that it’s not a problem because the lost family members have already been swept up in an indiscriminate drag net, such that the cameras can not find them.
The joke is on the DHS, and not it’s victims.
I was trying to point out that this feature may be even worse than that because it doesn’t even require a formal law enforcement request. If this becomes what it looks like, even private contractors will be able to access it without raising any alarms, further lowering the bar.