If FTX will fail, that would be big given their size. Failing FTX could drag others as well, including Binance. No?
I don't think it'd leave ftx to fail but it looks like they charge fees using that token so it might cause them problems with that (but I doubt they'd collapse just from one holder selling).
If they did collapse, they'd hurt crypto and binance. I don't know why binance would want to hurt themselves over this unless they have large cash reserves they want to invest in bitcoin or something (that's really not unlikely) or they could buy coinbase if ftx fails and dominate a lot of the market and also fast track their own regulation (who else will be wanting to own an exchange that might be crushed somehow or has very fierce competition)?
But then why would Binance announce it? I am sure they know that going public about their plans to liquidate FTT will bring the price of the token down. They've could first liquidate it, then announce it.
As another thought, maybe they're testing the strength of ftx and their reserves. If they publish they're going to sell the tokens publicly, does it give ftx some time to say they'll reach a settlement to buy those tokens rather than them being dumped on an exchange and driving the price down?
I see no other reason for them to announce it publicly unless a regulator they want to appease has it in their terms that acquisitions over certain amounts should be disclosed (I think US regulators normally have this set at a max of 10% of market cap of the "stock" you're disposing of for companies, it might be more depending on size and regulator). .