A few reasons, though as I note in another comment, I'm not an expert in spillover events, my area of interest kicks in about a week later. So there's a few:

1) People I trust are skeptical, including people who are opposed to gain of function research. I've found Angela Rasmussen to be one of the better voices in terms of discussing the evidence for a natural origin, but she's far from the only one.

2) We have had two naturally occurring coronavirus epidemics during my career. A third is all but inevitable -- I wrote a grant in October 2019 suggesting a novel coronavirus as an example case for a modeling exercise, for example (sadly, said grant didn't get funded). So for me, there's a very strong prior on coronaviruses emerging as significant public health threats.

3) At the same time, I've come to distrust many of the voices who push the lab leak hypothesis, either because they're obviously doing so for geopolitical reasons, or because they've become addicted to being "the lone voice in the wilderness", despite it not being a risky position to take.

4) The lab leak hypothesis, in terms of evidence, relies on WIV, the Chinese Government, the WHO, etc. being broadly incompetent except when it comes to the characterization of the initial cases when SARS-CoV-2 emerged, which is arguably the hardest part of any outbreak.

In the run-up to the second Iraq war there were a steady trickle of articles documenting the corruption of the intelligence process.

>Politicians hunting for excuses to do what they already want to do though, is definitely a thing.

Just to be clear: The people in charge are the CIA, not GWB. GWB was simply the right useful idiot at the right time in the right place.

> I feel that that could've been an honest mistake too.

There were a lot of indications that it was wrong even at the time, like the inspectors’ reports. We knew about the unreliability of the dodgy dossier and how baseless Khidir Hamza was. The satellite evidence was sketchy and the rest was contradictory. Al-Qaeda was also not there and we also knew that. Let’s not rewrite history: there is no certainty in intelligence, but anyone not in the CIA’s pocket knew it was most likely wrong, a far cry from what you need to legitimately attack a country.

According to Iraq general, WMD were moved to Syria about 6 month prior to invasion, then Syrian government used them against rebels.

HANNITY: So he had them.

SADA: Yes.

HANNITY: Where were they? And were they moved and where?

SADA: Well, up to the year 2002, 2002, in summer, they were in Iraq. And after that, when Saddam realized that the inspectors are coming on the first of November and the Americans are coming, so he took the advantage of a natural disaster happened in Syria, a dam was broken. So he — he announced to the world that he is going to make an air bridge...

HANNITY: You know for a fact he moved these weapons to Syria?

SADA: Yes.

HANNITY: How do you know that?

SADA: I know it because I have got the captains of the Iraqi airway that were my friends, and they told me these weapons of mass destruction had been moved to Syria.

BECKEL: How did he move them, general? How were they moved?

SADA: They were moved by air and by ground, 56 sorties by jumbo, 747, and 27 were moved, after they were converted to cargo aircraft, they were moved to Syria.

Seriously, I remember the Bush admin going after the wife of a CIA operative by leaking her identity after he spoke out about the war intel being bullshit. As someone who was following the Iraq war from the left side and pretty disgusted by it it definitely seemed like it was being pushed hardest by the GOP with anti-war information coming out of the CIA or even military. Granted leakers don't represent the opinions of an agency but this narrative that the CIA was the real villain (not that they aren't) that hoodwinked the poor GOP strikes me revisionist whitewashing.