Dude are you daft?
Are you implying every single informant (of which the FBI has THOUSANDS, they got in trouble for having too many post 9/11) is somehow connected to terrorists?
That's moronic. And the fact that they dumped him just further indicates he didn't know anything valuable about anyone of interest.
He was nabbed as part of an investigation into potential extremist orgs. Not terrorist ones. As far as I can tell, nothing he ever provided was used to investigate or charge anyone down the line with terrorism (or anything for that matter).
What is REALLY funny is one of the insular religious communities that the FBI was investigating at the time (and one that Ali may have spent some time studying scripture at) itself recieved TERRORIST THREATS from AMERICANS, no doubt due to the sort of reactionary bullshit disseminated by crazy websites like "Fuqra files" regarding "homegrown terrorist training camps":
https://en.wikipedia.org/wiki/Islamberg,_New_York
Fucking American terrorists!