To become a big whale, they would start of buying the whole existing market. Once done they are still not a gigantic whale and the price has reach 10 or 20$ / steem. Then, it starts to be much more expensive to be a gigantic whale, if they persist, steems would rise to 50 to 100$. Once there, even Facebook couldn't buy much more to become this bad actor gigantic whale.

Even if they could buy that much steem, it would bring so much value to the market cap that there attempt to destroy the platform would have the opposit effect and propulse it to the moon.

I think we call it checkmate !

I don't know if they are worried about Steem but they should !