Does that say much? They're the biggest buyer because USDT is the biggest stablecoin.

Isn't that reversing the logic? If FTX bought more USDC than USDT, the scales would've changed.

Also, the fact that FTX has never called out Tether or at least pushed for a proper audit is indicative that they are more likely to be in the scam than merely buying from them because they believe to be solid.

Your logic is backwards. They don’t buy more Tether than other stables. (Well they do but that wasn’t the point)

The point is they are Tether’s largest customer. They buy more Tether than anyone else.

I still don't see what the problem is. Their customers want USDT. They buy USDT so their customers can access it. Looking around on their site, it looks like they support USD alongside USDT, so it's not like they're strongarming their customers into using USDT. Calling that shady is like calling a stock broker shady because they're the largest buyers of [insert shady/overhyped company here].

They are tethers largest customer because they're the largest exchange and tether is the largest stablecoin. Stablecoins in general were created because offshore exchanges had trouble dealing with traditional banks since the whole point of being offshore is not following US regulations.