I have friends from a job I haven't worked in for years. Intelligence is a little different, obviously, but it's not completely crazy.
> who supposedly didn't care about MI6 anonymity protections and were willing to share their secrets with dudes in the private sector in exchange for money.
Most sources share their information with the CIA or MI6 for money - why not share them with this guy for money? Especially if he's a former spy and someone you personally know.
I disagree that the setup makes no sense.
> being a hired project designed to only seek politically incriminating information was doomed to be biased from the start, especially in light of the foregoing
This point makes sense, but this information was attached to articles about this dossier from the very beginning, if I recall correctly. You can look up the original buzzfeed article and see if they listed the source. Maybe they didn't. But it was widely known and reported for a long time.