Why do markets drop?

2 Reasons.

#1 Making profit

What's the purpose of buying if you are not going to sell at some point? And why do we sell? To make profits.

#2 Buying at cheaper price.

When you are a market maker, or even a small whale, you have the ability to control the price of the asset, shift the market the way you want in your favor.

If you have got a dollar, and that dollar can buy you an apple, Why not buy 2 apples for the price of 1$ instead of one?

How?

By Stiring fear that the apple will rotten in your adversary's hands, so he will sell you his apple for half the price, only for you to sell it for a dollar and a half.

That's how things are run in crypto.