Oh, this is a golden area. It's not moronic especially (I mean, it IS moronic, but that's not the biggest part). No, this is the Council's racism at work. Remember, the Council is the same organization who consider humanity to be bullies for the fact that humanity's still reacting to the First Contact War, where their introduction to aliens and the Council was to be shot at and invaded by the turians, because they broke laws they didn't know about by an organization they'd never heard of led by aliens they had no idea existed. That whole 'trial' is a show, a sham. They don't believe anything that the humans offer. It's only when a quarian, a non-human, backs up humanity and puts something forward that they believe.
This would make sense if the Quarians were in any way seen as a respectable species in ME1, but they aren't. And didn't the council stop the Turians from destroying the humans in the first contact war?
You're coming up with a whole lot of headcanon for something that's fairly understandable: a human comes forward, accuses your top agent of being a traitor with
zero evidence and then some idiot starts talking about a vision from some beacon. A logical conclusion to the first council meeting would be: "Commander, Admiral: stop using drugs and don't bother us with this sh*t again"
Giving Saren access to Nihlus files is ridiculous though, I agree, but the outcome of that hearing is not. If the council had acted on the first hearing now that would've been hilarious.
Because earlier, they dismissed eye-witness testimony on the grounds that it was 'hardly compelling.' The investigator was Garrus, who is not one of C-Sec's favorite operatives, and he apparently was investigating on his own for all of a day. Saren, the accused, was given access to Nihlus's records, the victim. That trial was criminally incompetent. The Council wanted humanity to sit down and shut up and adhere to the status quo, stop rocking the boat. The last thing they wanted was for the humans to be right about questioning the loyalty of their top agent. But once they have a non-human in their corner, suddenly they listen. Even though Tali's evidence really should be on shakier ground than an eye-witness record, since Anderson and Udina were surprised she'd gotten any data from the geth memory core. But no, THAT evidence is irrefutable. It says to me that they were shielding Saren right up until they got proof that there was more out there and humanity wouldn't let it go and they would HAVE to do something.
Eyewitness accounts are never reliable. I'm seriously surprised they're still allowed in court in the real world. There's been a tonne of research done and all conclude that eyewitness accounts are shitty to horrible. Ask 10 different people what color shirt someone was wearing and you get 5 different answers (with a good chance all 5 are
wrong). It's hilarious.
I don't think it has anything to do with a Quarian bringing forth the evidence. As said, Quarians aren't really popular either, probably even less so than humans. They just want something solid instead of you making baseless claims... and apparantly an audio recording is a solid thing in the MEU that can't be tampered with.
...Yeah, have I mentioned that I really don't care for the ME1 Council and consider it better for the galaxy as a whole if they die during the battle of the Citadel?
They rarely make it to ME2 in my games, but I also rarely purposely kill them.