Why did all cryptocurrencies drop at the same time?
All crypto coins are linked to Bitcoin, or Ethereum. If you look at the graphs of these 2 coins, and see the time stamps when they rise and fall, you'll see they are identical. The altcoins all follow suit with these time stamps.
What people don't realize is that the entirety of crypto is controlled by whales (a.k.a The rich). Around 28% of Bitcoin is controlled by 10 people. So when you see a sharp price increase in Bitcoin, every altcoin follows suit. Either a few minutes after the price pump to a few hours (when the price increases more), a big dump happens when the whales sell off the coins they bought initially.
It's a rinse and repeat scenario.
Another case of price manipulation are the crypto bots, which buy and sell to increase a fake price increase, to get you to buy a specific coin. These are controlled by whales - who tell social media influencers to pump these coins, and eventually you'll learn that the only ones getting rich off crypto are the whales.
The only real way to get rich off crypto is to gamble on a coin from the very beginning. The other way is to have insider information when the whales make a massive buy, or do short trades. Every short trade comes with capital gains tax, plus gas fees, and any other fees. Long term holds will always be in control of the whales.