That's generally true, yes - as you say, for the most part. Though - and I'm not saying people should be surfing JUB at work, though some here say they have the freedom/flexibility to do so; especially if they are the boss.

- it can be different in a corporate environment where hundreds (even thousands) of computers, no matter where internal to the organization, are putting out the same identical IP address (or IP range, like a block of 20 addresses) to the outside world because that's the hardware firewall or corporate web proxy's IP. Web cafes or libraries, too, I suppose, depending on how the connections are configured. Also, if someone really wanted to go to the effort to impersonate a supporter or a back-and-forth conversation on JUB, I'm sure they'd just use a Proxy service or other anonymizer.
I didn't hear the "sockpuppet" terminology but we've all seem conversations where it's just two people at all hours of the night (and day!) back-and-forth in a thread that would not only be better suited for PM but looks suspiciously like
someone interacting with themselves, lol. (Although I suppose, philosophically, it could be asked that if you can't interact with yourself, with whom can you in this world?

)