2. Anon tells other anons he got the UDIDs from a laptop.
3. Other anons tell more anons it was a government laptop.
4. Release group writes "FBI laptop" in their pastebin.
(5. ??? --> 6. Profit!)
The heterogeneity and disorder in Anonymous (at least it was like this back in the day) means that the chain from leaker to releaser -- usually passing through several people and IRC channels -- plays out a bit like a game of telephone. This serves to protect the leakers, but it can mess with some of the details.
The releaser of the data mentioned the name of a specific FBI agent and claimed the data had a specific file name containing the acronym of an non-profit organization set up to share data between private industry and intelligence organizations.
Details like that don't emerge over the course of a game of telephone. If this story is correct, and the data was not in the possession of the FBI, someone deliberately decided to make up an elaborate lie.
The FBI Agent (Christopher K. Stangl) appears in a recruiting video for cybersecurity experts. It is no sign of secret knowledge when his name is used.
It's entirely plausible that you work for the FBI and are trying to discredit talk of the FBI's involvement by proposing relatively poor arguments to the contrary.
During the second week of March 2012, a Dell Vostro notebook, used by Supervisor Special Agent Christopher K. Stangl from FBI Regional Cyber Action Team and New York FBI Office Evidence Response Team was breached using the AtomicReferenceArray vulnerability on Java, during the shell session some files were downloaded from his Desktop folder
I don't think it is helpful to make excuses for Anonymous. If you'll allow me to abuse the ethical alignment terms: They appear to be a chaotic neutral, not a chaotic good. I'm not sure it makes much difference if they lied or are incompetent. Especially since there really isn't a specific 'they'.
The chain of events could have been:
1. Blue Toad either gets hacked, or gives their data to the FBI or someone else.
2. Somehow this data ends up on an FBI agent's laptop.
3. Anonymous breaches the laptop and gets the data.
4. Anonymous sees all the UDIDs and mistakenly thinks, "Apple and the FBI must be in cahoots!", and publishes it.