Is this true?
Yes.
What are your knowledges about this?
Bitcoin doesn't have a central authority and that is a feature of Bitcoin. In the real world, fiat can be forced to return with a court order or a lawsuit. This can only be fair if the judges are fair about it and it wouldn't always be the case. Bitcoin can't have anyone to judge if your coins are lost or stolen and rightfully belong to you. It seems logical for everyone to be responsible for their own coins.