Down feathers are very light, resilient and insulating fiber flakes of thousands of hairs from especially waterfowl. Goose down insulates better than duck down. If it gets wet, it looses her insulation value. You can wash a down comforter, but you should then dry it quickly, airy and thoroughly. Down plucking is an endless job. But for some sleep comfort you maybe can spend some winter days at slaughter and plucking to this job.
The blanket is usually stitched (sewn) in several subjects to prevent the content gets accumulated on a few places (corners). This gives you a more even distribution.

(In Polish, Hungarian and Chinese farms (were?) geese to 4 times during their existence plucked alive. Which is banned in the EU. Rightly, I think!)

What's the difference between ignorance and indifference ?

I do not know and I do not even care.