i can understand blob for radios: by only using a signed blob you are restricting a malicious user from abusing the radio.

However, the problem with binary blobs is that they are binary blobs: no sources, can't make changes, can't adapt them to work on a new system, can't audit them. Free folks have always argued that a computer will never be free if there are binary blobs in there

(well: the last part is not really true, there is always a way to have a custom firmware, or make an audit, but the manufacturer will do that only for elite customers. Not for open source folks.)