Bitcoin is completely decentralized, one or more individuals, institutions, and groups do not control Bitcoin. Bitcoin whales are organizations, individuals, and groups that hold 1000 or 1000+ bitcoins. Yes it may be somewhat true that bitcoin whales may temporarily have some effect on the bitcoin market. For example, if Michael Sheller sells all his bitcoins in the market at once, the bitcoin market will be affected to some extent. Bitcoin whales will not completely destroy the Bitcoin market.
The correct name is Michael Saylor and at current his company MicroStrategy holds more then 120k bitcoins and he buys at dips but even if he sell the effect would be temporary dump on the prices but in long run it will rise.The whales cannot directly have the manipulation so they also try to create FUD so that there is panic in the market which results in weak hands selling to strong one's at discounted rates.But nobody can control the bitcoin network which is true decentralisation nature of it.