My point is:
It is way (probably multiple times?) easier for the exchanges to create fake BTC liquidity. Because of this their price pressure/manipulation capability is magnitudes higher on pushing BTC price down than on push it up.
Yep, really easy compared to fiat manipulation. But they'll be in trouble if some users withdraw a lot of bitcoin. I believe when this happens they'll likely start selective scamming by disabling withdrawal for some users and that's when they screwed up.
To be honest it's really difficult to find out exactly how many BTC an exchange hold. They can lie, fake it, and so on. Which is why leaving your coins on exchange is terrible.