Can the down jacket be washed with a washing machine? How come?

I found that down jackets can be washed by washing machine. The following are my usual washing methods:

1. Use mild detergent: choose a detergent specially used for washing down jackets.

2. Wash with cold water: it is best to wash with cold water.

3. Use low-speed gentle mode: choose low-speed gentle mode for washing.

4. Batch washing: multiple down jackets need to be washed at the same time, preferably in batches.

5. Don't rub too much: try to avoid rubbing down jackets too much.

6, natural drying: flat in a ventilated place to dry naturally.