Hermione gave Ron a look that clearly suggested he was completely daft before she even opened her mouth to bother explaining.
"Whether I'm thinking about why or what happened in order to receive that bottle of blood, or I'm thinking about what I could do to try and stop the Death Eaters, it's equally as frustrating! I can't take back whatever it is I did, I can't make that okay and I can't do anything to stop it happening again."
So replacing one line of thought with the other was just pointless.