Why has the depth of altcoins been withdrawn frequently this year, and each withdrawal is a large price correction?

Because there are very few market makers serving altcoins, especially tokens with a market value of less than 2MM, then:

These coins still have contracts, and everyone should guess who is providing services for altcoin contracts and who is acting as your counterparty!

If the price rises/falls sharply in the short term, this counterparty will be forced to hold a large number of short/long positions, and naturally needs to release the pressure of holding in the opposite direction!